Precision Nutrition Certificaiton Textbook Table of Contents, Introduction and Chapter 1

PRefACe 4

INtRoDuCtIoN

What is good nutrition? 7 Introductory case study 21

UNiT 1

Nutritional science 23

ChAPteR 1Cell structure and function 25

ChAPteR 2Food intake, digestion and absorption 41

Case study 65

ChAPteR 3Energy transformation and metabolism 67

Case study 94

ChAPteR 4

Energy balance in the body 97

Case study 116

ChAPteR 5

Aerobic and anaerobic metabolism 119

Case study 136

ChAPteR 6

Macronutrients 139

Case study 162

ChAPteR 7

Micronutrients 165

Case study 189

ChAPteR 8

Water and fluid balance 191

Case study A 205 Case study B 207

ChAPteR 9

Special needs 209

Case study 240

UNiT 2

Nutritional practice 243

ChAPteR 10

Step 1: Preparing for your client 245

Case study 264

ChAPteR 11Step 2: Collecting preliminary client information 267

Case study 301

ChAPteR 12

Step 3: interpreting client information 303

Case study 323

ChAPteR 13

Step 4: Providing a nutrition plan 325

Case study 361

ChAPteR 14

Step 5: Nutritional supplementation 363

Case study 372

ChAPteR 15Step 6: Setting behavior goals and monitoring 375

Case study 395

ChAPteR 16Step 7: Making nutritional adjustments 397

Case study 420

ChAPteR 17Step 8: Providing continuing education and support 423

Case study 441

GlossARy 443

APPeNDICes 455

RefeReNCes Unit 1 462 Unit 2 470

Table of conTenTs

PRefACe:

How To use THis TexT

Students usually wonder whether what they learn in school can be applied to the “real world.” When the heck will they ever really need to know the cosine of a right angle, or Kepler’s laws of planetary motion? When they’re 40-year-old accountants, will they need to remember the Krebs cycle and the enzyme responsible for forming citrate?

I know this well. As a student, I asked those questions too. Now that I’m the teacher, it’s time for me to be frank with my students. Will you ever need to know this again? Probably not. My students will probably never need to know cosines again, unless they become engineers. They’ll probably never concern themselves with the laws of planetary motion again, unless they go to work for NASA. And they’ll probably never need to discuss the Krebs cycle – ever. Unless they sign up for this certification, that is.

If you’ll never need this information in the “real world”, then why should you learn it? Good question. The typical answer – something along the lines of: “It’ll make you a smarter, well-rounded person” – isn’t all that inspiring. Thus, I usually respond with: “Well, very few of you know what you’re going to be ‘when you grow up.’ Heck, I don’t even know and some might argue – others not – that I’m already ‘grown up.’ You’d better get exposed to everything that’s out there now. Further, and call me crazy, some of this info might actually be interesting to you. You might just decide to go down this career path because of it.”

I know, I know. You’re still not convinced. Yet I think it makes a lot of sense. This basic information – math, physics, biology, etc. – may not seem relevant to your life right now. But you just never know what career path you’ll be on or what hobbies you’ll develop as you roll down the road of life. If you’d told me 15 years ago that I’d earn a PhD studying the biochemistry of nutrition, I’d have said you were nuts. But here I am, writing this manual and studying nutritional biochemistry. So act like a Boy Scout, folks, and be prepared for anything.

That said, some instructors (hopefully not me) can strip the fun right out of learning. Many of them simply recite or expect you to regurgitate facts or foundational information. Often this information lacks any practical application. It’s no wonder that students get lost and uninterested. There’s little to spark their imagination. That’s when they start wondering whether they’ll need to know things.

I often wonder what would happen if these instructors came up with some really applied stuff instead. For example, instead of just describing, defining, and deducing the mathematical formulae Kepler used, why not create a NASA mission out of the exercise? Launch a hypothetical space craft into orbit, bound for Mars! Then, using Kepler’s laws, chart your course so that you connect with Mars at the right time and place. That’d probably be fun, even with all the math. As you can see in this example, the foundational knowledge is still critical. You’d have to know Kepler’s laws before firing up the rocket engines. Yet there’s now a reason to get excited about the information – you’re going to Mars!

5inTroducTion | Preface How to use this text

In this course, I’ll provide a lot of foundational knowledge (information about your cells, your digestion and absorption, your energy transfer processes, your metabolic controls, and more) and a lot of applied knowledge (case studies, strategies for working with real-world clients, questionnaires and assessments to use with your clients, psychological strategies for getting clients excited about working with you, and more). By the end of this course, I expect you to understand how the body works, how to troubleshoot based on physiological considerations, how to intelligently discuss a host of nutritional issues, and how to convince your clients that you have a deep knowledge of the subjects with which you’re helping them. You’ll need this basic science so that you can do your job properly, in the “real world.” However, thankfully, we won’t just stop at the science. This certification course is split up into two units so that we can cover both nutritional science (Unit 1) and the art of nutritional coaching and practice (Unit 2).

UNiT 1 CovERS All ThE SCiENCE yoU’ll NEED To UNDERSTAND ThiNgS likE:

• How and why your cells work the way they do

• How carbohydrates, fats, vitamins, minerals, and other nutrients interact with your cells

• How food becomes energy for maintenance functions, physical work, and repair

• How your body balances out the food you eat with the work it does

• How exercise affects nutritional needs and how nutrition affects exercise

UNiT 2 CovERS All ThE hANDS-oN, PRACTiCAl kNoWlEDgE yoU’ll NEED To UNDERSTAND ThiNgS likE:

• What it means to be a good coach

• How to prepare for clients

• How to interact with different personalities

• Which questionnaires and assessments are most valuable

• How to meet clients where they are (not where you want them to be)

• How to keep clients progressing from day one until they reach their goals

That may seem like a lot to learn. Don’t get overwhelmed. We’ve included tools to enhance your learning experience as you work your way through the two units. Look for things like:

ChAPTER oBJECTivES

Each chapter contains clear objectives at the beginning. This will give you goals before you even start reading. It’ll also help you review and self-test before the fateful exam time.

ChAPTER SUMMARiES

At the end of each chapter, we’ll clearly summarize the most important points made in the chapter. These will confirm that you’ve learned what was outlined in the objectives, and provide another excellent tool for exam review.

kEy TERMS

At the beginning of each chapter, we’ll list a number of key terms used in that chapter. The first time one of these key terms appears in the text it’ll be highlighted and a definition will be provided in the margin. These terms will also appear in a glossary at the end of the manual. Familiarize yourself with each key term, because you’ll likely see it again (you know, like, at exam time).

6 inTroducTion | Preface How to use this text

CASE STUDiES

Most chapters end with relevant case studies. These will give you “real-life” examples of applied performance nutrition. Each story describes a client’s nutritional challenges and then provides practical solutions to illustrate how these challenges can be overcome.

REFERENCES

At the end of the manual, we’ll provide a comprehensive list of textbooks and studies used to create this certification. If you’re interested in learning more about performance nutrition, you can look up and read more of this primary source literature.

RECoMMENDED READiNg AND RESoURCES

No single manual or course can ever be sufficient if your goal is to master a subject. Therefore, at the end of the manual, we provide you with a host of additional resources that we think you’ll benefit from exploring.

Along with worrying about “real-world” application, if you’re anything like I was as a student, you’ll be wondering two things as you begin this course: Am I going to pass the exam? And is this actually going to make me a better fitness professional? We’ll provide you with all the learning tools necessary to help you pass the exam with flying colors. (Of course, you still have to study. Sorry.) As for the second question: If you master both the basic science (Unit 1) and the applied art (Unit 2), you’ll emerge as a highly trained fitness professional who has the knowledge to back up what you’re recommending, as well as a fool-proof system to deliver outstanding, reproducible results. Feel like a trip to Mars? Let’s get started!

INtRoDuCtIoN

wHaT is GooD NutRItIoN?

Chapter objectives

key terms

limiting factors

good nutrition defined

how you can help clients improve their nutrition

your scope of practice

Applying nutrition technologies

8 steps to effective nutrition coaching

The purpose of this course

introduction Summary

8 inTroducTion | What is good nutrition?

objectives

in this chapter, you’ll learn the importance of a good

nutritional intake for overall physiological function and

the body transformation process. You’ll understand the

definition of good nutrition, and you’ll be able to help

your clients improve their daily food intake – and their

lives. You’ll understand your scope of practice in making

nutritional recommendations. in understanding what you

can and cannot recommend, you can shape your coaching

strategy to include both sound training advice and the

systematic application of nutrition technologies.

KeY teRms

Limiting factors

Genetics

Metabolic

Energy balance

Nutrient density

Health

Body composition

Performance

Outcome-based

Laws of thermodynamics

Positive energy balance

Negative energy balance

Insulin resistance

Calorie density

Satiation

Ergogenic

Social support

Medical nutrition therapy

Cross-referral system

9inTroducTion | What is good nutrition?

limiting factorsTo achieve great results with a client, master one crucial skill: the ability to find your client’s limiting factors – the things that stand between them and reaching their goals – and remove them. That one skill will take you from being a good coach to being a great coach; and from a student to a master. That one skill alone will get more business than you can handle, and better results than you ever thought possible.

Find your clients’ weakness. Find what’s holding them back. Find what’s keeping them from succeeding. And fix that.

There are many limiting factors. More, in fact, than we could possibly cover in this manual. After all, people have lots of different genotypes, lots of different lifestyles, and lots of different ideas about what’s “good for them” (and what’s not). However, if you look at people’s limiting factors in terms of their ability to be healthy, to lose fat, and to gain muscle, there are really only three types of limits:

1. Their genetic makeup;

2. Their physical activity patterns; and

3. Their nutritional habits.

Everything else really just falls into one of these three categories, doesn’t it?

lImItING fACtoR 1: GeNetICsAre your clients limited by their genes? I seriously doubt it. Out of the thousands of people I’ve worked with over the years, I can’t remember a single one that couldn’t improve in some very significant ways, despite their genetics. Few people ever come close to realizing their genetic potential for health and fitness. Don’t assume that your clients are standing on the brink of their genetic upper limit.

Of course, we must be realistic. Each of us has certain, very real, genetic limitations. For instance, most of your clients will not be equipped to play quarterback for the Patriots, play center for the Lakers, or win the Tour de France. In other words, they may not have the genetic makeup to reach the upper limit of elite human performance. Despite this limiting factor, all clients can still improve their health, lose fat, and/or gain muscle by getting the right advice and implementing it. In fifteen years of working with all kinds of people, from office managers to elite athletes, I’ve yet to see a single case where we couldn’t improve their body composition, health profile and performance, significantly.

lImItING fACtoR 2: exeRCIseIs your client’s physical activity pattern their limiting factor? It’s possible, especially if an individual is completely sedentary. Indeed, if their daily activity involves nothing more than moving from one piece of furniture to another, their exercise habits (or lack thereof) are probably one of their limiting factors. Getting fitter, leaner, and healthier all require both an active lifestyle as well as a commitment to purposeful, regular, intense exercise. If a client sits at a desk all day and then goes home to sit some more, they’re probably cultivating metabolic decline, fat gain, muscle loss, and lifestyle-related disease. They just don’t take enough steps in a day. When the number of steps people take per day are measured, those taking under 5,000 steps are considered sedentary and at higher risk for early death, disease, and being overweight. In comparison, those who do 10,000 steps are considered active; not surprisingly, they have lower body weights, less body fat, and improved health.

lImItING fACtoRAnything that makes it more difficult for a client to achieve optimal results

GeNetICsSpecific, inherited DNA of an organism, which influences what they become, although environment also plays a key role in the expression of an organism’s genetic code

metABolICPertaining to the chemical reactions and physiological processes necessary to ensure life


eNeRGy BAlANCeRelationship between all sources of energy intake and energy output; an organism is said to be in energy balance when energy flow into the body and out of the body is equal; often evidenced by a stable body weight

NutRIeNt DeNsItyFoods that provide substantial amounts of nutrients with only the necessary calories

When people increase their level of this type of basic physical movement, in conjunction with doing at least five hours of purposeful high intensity exercise per week, the magic starts to happen.

However, exercise alone isn’t usually enough. As I’ve seen repeatedly with clients, and as research at major universities is starting to show, many people lag behind because of a different limiting factor, even with a great exercise program. A recent study examined overweight participants who were either assigned to a control group for 16 weeks (where they didn’t exercise at all) or an exercise group for 16 weeks (where they exercised for three hours per week, performing strength exercise with an Olympic weightlifting coach, and two hours per week, performing circuit training with a group exercise instructor). During this time, researchers collected data on body composition and a host of other measures. As you might have expected, the exercise group did get better results than the control group, but these results were… well… embarrassingly unimpressive:

The control group gained 1 lb of lean mass, lost 0.5 lb of fat, and lost 0.5% body fat

The exercise group gained 3 lb of lean mass, lost 2 lb of fat, and lost 1.5% body fat

Obviously, the exercise group did better and the exercise helped a bit. However, if I were your client and I had paid $4,000 to $8,000 for 80 training sessions (five sessions per week for 16 weeks), and I left having lost only 2 lb of fat after four months, I’d probably demand my money back, and your head on a platter. Is this what our clients can expect? They come to us overweight and unhealthy and after spending a lot of time, effort, and money, they leave only slightly less overweight and unhealthy. If it were me, I would have rather sat at home on my arse; read more books; learned to play the guitar; learned to speak French… or a host of other activities instead of wasting my 80 hours and several thousand dollars on two measly pounds of fat loss!

I’m exaggerating my indignation here. But only just a little. Purposeful exercise alone, while marginally better than nothing, never seems to produce the results that purposeful exercise plus increased general physical activity (i.e., more steps) plus nutritional control can produce.

People who are overweight and unhealthy, with too little muscle and too much fat, usually have a few problems. They probably don’t move enough and they eat too much (or at least, too much of the wrong stuff). You should definitely get them moving more; that’s a prerequisite for success. But getting them to move more for a few hours per week isn’t usually enough. Their real limiting factor is more than their exercise. It’s not their genes. It’s not their training program. It’s what they’re eating – and sometimes, more importantly, what they’re not eating.

lImItING fACtoR 3: NutRItIoNWhether your client wants to gain muscle, lose fat, pursue a healthy lifestyle, or even compete at the highest levels of sport, the most important limiting factor is almost always nutrition. Poor nutrition is what holds clients back. Good nutrition is what propels them forward. Good nutrition feeds muscle and helps shed fat. It improves nearly every measurable health marker. It drastically improves recovery and mood, so clients can exercise – whether it’s purposeful or just part of their daily lifestyle – harder, longer, and more frequently. Good nutrition will get them the body they never thought they could have. And it’s the most significant factor determining their outcome.


good nutrition definedSince this entire course is devoted to teaching you exactly what good nutrition is and how to help your clients eliminate poor nutrition as a limiting factor, it’s important to have a working definition of “good nutrition.” If you ask a hundred different people what “good” or “healthy” eating means, you’ll likely get a hundred different answers! Some think good nutrition means eating fewer sugary desserts. Others think it means eating more fruits and vegetables, less meat, and/or fewer carbohydrates. And then there’s the often-cited, commonsensical, and largely meaningless “balanced diet.” While most of the definitions you’ll hear are simple and easy to remember, most of them will be incomplete and some of them will be flat-out wrong.

This course will reorganize your understanding of nutrition. You’ll dump out all the ridiculous, oversimplified, often erroneous media mythology you’ve been exposed to in order to make some room for the right information. We’ll teach you how to judge the “goodness” of a nutrition plan. Let’s start with four important criteria that all good nutrition plans must meet.

1. Good nutrition properly controls energy balance.

2. Good nutrition provides nutrient density.

3. Good nutrition achieves health, body composition, and performance goals.

4. Good nutrition is honest and outcome-based.

Let’s now discuss each of these in more detail.

1. GooD NutRItIoN PRoPeRly CoNtRols eNeRGy BAlANCeThe phrase “energy balance” represents the relationship between “energy in” (food calories taken into the body through food and drink) and “energy out” (calories used in the body for our daily energy requirements). This relationship, defined by the laws of thermodynamics, dictates whether weight is lost, gained, or remains the same.

However, there’s a lot more to energy balance than its physical manifestation in weight change. Energy balance also has a lot to do with what’s going on in your cells. In this manual, you’ll learn more about what’s happening in your body on the cellular level. Both a positive energy balance (more energy in than out) and a negative energy balance (more energy out than in) affect everything from your metabolism to your hormonal balance to your mood. For example, a study that examined military recruits found that severe negative energy balance led to massive metabolic decline and an inability to concentrate; it reduced thyroid hormone production, testosterone levels, and physical performance. The same is true in those with anorexia nervosa: they lose physical fitness, metabolic fitness, mental fitness, bone mass, and muscle mass.

An intense negative energy balance does lead to weight loss. But so does getting thrown in a prison camp or being in a poor African village without adequate food. And that’s exactly what our bodies think when we impose a large negative energy balance: I’m starving. All “non-survival” functions including reproductive function, metabolic function, and brain function slow or shut down.

On the other hand, a positive energy balance from overfeeding (and/or under-exercising) has its own host of repercussions. Weight gain is the most obvious consequence, but health and cellular fitness suffer too: plaques can build up in our arteries; blood pressure and cholesterol can increase; we can become insulin resistant and begin to suffer from diabetes; our risk for certain cancers increases, and the list goes on.

heAlthState of physical well-being and optimum function that should be assessed through medical tests, including blood assessments, cardiovascular tests, and other screening modalities

BoDy ComPosItIoNRelative relationship between lean body mass (which includes bone mass, body water, muscle mass, and organ mass) and fat mass (which includes adipose tissue and intra-tissue fat deposits)

PeRfoRmANCeFunction, action, or operation, whether athletically or in daily life

outCome-BAseDUse of specific, measurable outcomes and evidence to make decisions, rather than nebulous or dogmatic definitions of what’s “good” or “correct”

lAWs of theRmoDyNAmICsPrinciples that govern energy exchange, including heat exchange and the performance of work

PosItIve eNeRGy BAlANCeWhen energy flow into the body exceeds energy flow out of the body, often evidenced by an increasing body weight

NeGAtIve eNeRGy BAlANCeWhen energy flow out of the body exceeds energy flow into the body, often evidenced by a decreasing body weight


Good nutrition programs help to properly control energy balance. Good nutrition prevents excessive swings in either direction (positive or negative) and the body can either lose fat or gain lean mass in a healthy way.

2. GooD NutRItIoN PRovIDes NutRIeNt DeNsItyNutrient density is the ratio of nutrients (vitamins, minerals, fiber, etc.) relative to the total calorie content in a food. Therefore, a food with a high nutrient density would contain a large amount of key nutrients (protein, iron, zinc, B vitamins, etc.) per 100 calories of food.

Positive energy balance: WEIGHT GAIN

Neutral energy balance: WEIGHT STABLE

Negative energy balance: WEIGHT LOSS

Calories in = Calories out

Calories in < Calories outCalories in > Calories out

Energy expenditure(Calories burned)



Energy intake(Calories eaten)



FIGURE 0.1the RelAtIoNshIP BetWeeN CAloRIes IN AND CAloRIes out

High versus low nutrient density

tABle 0.1

exAmPles of fooDs WIth hIGh NutRIeNt DeNsIty exAmPles of fooDs WIth loW NutRIeNt DeNsIty

bright or deeply coloured vegetables Table sugar

bright or deeply coloured fruits soda / soft drinks

High fibre, unprocessed grains white flour

lean meats ice cream

INsulIN ResIstANCeCondition in which normal amounts of the hormone insulin are inadequate to produce a normal response from fat, muscle, and liver cells


Calorie density is defined as the ratio of calories (which are merely units of potential energy in food) to the actual weight of a food. Therefore a food with high calorie density would have a lot of calories per 100 g of food while a food with low calorie density would have few calories per 100 g of food.

As you might imagine, the best combination of nutrient and calorie density for improving health and promoting fat loss is a diet high in nutrient-dense foods (a lot of nutrients per calorie) and low in calorie-dense foods (few calories per gram of food weight). Such a diet would have the following benefits:

• Easily controlled calorie intake (without calorie counting)

• Longer periods of satiation, or satisfaction/fullness, after meals

• Difficulty overeating

• A higher total essential nutrient intake

• More essential nutrients per volume of food

Key nutrients found per 100 calories of sample foods

tABle 0.2

PRoteIN fIBRe IRoN ZINC thIAmIN RIBoflAvIN NIACIN B6 B12 (g) (g) (mg) (mg) (mg) (mg) (mg) (mg) (mg)

spinach 14 g 10 g 12.5 mg 2.5 mg 0.4 mg 0.9 mg 3.3 mg 0.9 mg —

lean beef 14 g — 1.4 mg 3.2 mg 0.1 mg 0.1 mg 1.9 mg 0.1 mg 1.2 mg

Bagel 3.8 g 2.2 g 1.3 mg 0.3 mg 0.2 mg 0.1 mg 1.7 mg 0.1 mg —

low-fat milk 6.7 g — 0.1 mg 0.8 mg 0.1 mg 0.3 mg 0.2 mg 0.1 mg 0.7 mg

soda 0.1 g — 0.1 mg — — — — — —

Bold type: high nutrient density italic type: Medium nutrient density regular type: low nutrient density

High versus low calorie density

tABle 0.3

exAmPles of fooDs WIth hIGh CAloRIe DeNsIty exAmPles of fooDs WIth loW CAloRIe DeNsIty

cookies fresh vegetables

crackers broth-based soups

butter fresh fruits

bacon chicken breast

CAloRIe DeNsItyEnergy provided per unit of food; high caloric density foods provide many calories in a small portion while low caloric density foods provide fewer calories in a large portion


Conversely, for someone interested in weight or muscle gain, the recommendation above might be altered in favor of high-nutrient-dense, high-calorie-dense foods. This would allow for increases in both nutrient intake and calorie intake, both essential for gains in lean mass and total body weight.

3. GooD NutRItIoN AChIeves heAlth, BoDy ComPosItIoN, AND PeRfoRmANCe GoAlsGood nutrition is more than about weight loss or gain, which are just transient indicators of energy balance, since energy balance and weight can change from one day to the next. Therefore, finding a long-term set of dietary habits should be based on the intersection of the following three goals:

1. Improved body composition

2. Improved health

3. Improved performance

Yes, a large majority of your clients are working out with aesthetics in mind. They want to lose fat, gain muscle, achieve a flat stomach, and generally look great naked. Because of these strong motivators, they can easily be lured into a world of powerful drugs, invasive and risky surgeries and ridiculous crash diets. While these short-term strategies can sometimes (and temporarily) improve the way your clients look in the mirror, in the long run such strategies can often sacrifice their health and well-being.

Rather than focusing solely on the visual outcome of body composition, focus on improving a client’s health and performance as well. Employ nutritional strategies that also reduce blood lipids, increase insulin sensitivity, reduce diabetes risk, increase good cholesterol, reduce body fat percentage, and increase lean body mass. In addition to boosting health and body composition, your recommendations should help your clients improve performance, regardless of whether they’re elite athletes or only watch them on TV. Depending on your clients’ goals and activities, performance outcomes range from improved energy levels and stamina to improvements in athletic performance at the elite, world-class level.

While there is a lot of overlap here (for example, if someone begins to look better, they should also begin to feel better and perform better), the overlap isn’t all-inclusive. Some plans help folks lose weight in a hurry while sacrificing their health and performance. Other programs cater to the “I just want to be healthy” market. While some of these approaches (calorie restriction, the avoidance of certain foods, high doses of certain vitamins, and more) can improve one or two indicators of health, many strategies actually worsen health. Finally, there are a lot of performance enhancement programs out there that include powerful ergogenic (performance-enhancing) drugs, crash dieting, diuretics to make weight for competition, unresearched nutritional supplements, and more. While these approaches might improve performance briefly, they often lead to a degradation of health, which inhibits long-term achievement.

Focusing strictly on any one of the goals above to the exclusion of the others can lead to problems. An excessively single-minded focus on “performance” or “weight loss” or “health” might, in some cases, actually produce negative long-term consequences. It’s your job to prevent this type of “coaching gone bad.” Provide a nutrition plan that improves the way clients look, feel, and perform.

To ensure you remain on track, we’ve provided a host of metrics (questionnaires and assessments) later in this manual. These metrics will help you monitor each of the three domains above, to ensure that each area is looked after properly.

sAtIAtIoNThe state of being satisfactorily full

eRGoGeNICPhysical or mental performance-enhancing strategies


4. GooD NutRItIoN Is hoNest AND outCome-BAseDWhile good nutrition controls energy balance, boosts nutrient intake, and targets health goals, body composition goals, and performance goals, it also has to be honest about whether it hits the mark. After all, how many times have you heard the following:

“I eat really well” …but…“I’m still 20 pounds overweight.”

“My diet is perfect” …but… “I often feel sluggish and fatigued.”

“I make good nutritional choices” …but… “I’ve got high blood pressure, cholesterol, and type II diabetes.”

Is it possible that someone could eat really well and have a “perfect” diet yet be overweight, fatigued, and riddled with lifestyle-related diseases? Sure, it’s possible, but it’s not likely. Most people who believe they’re “doing a good job” but who don’t have the physique or the health profiles to show for it, simply aren’t. Either they have a good plan that they’re not executing or their plan isn’t very good. As someone committed to finding limiting factors and removing them, it’s your job to help your clients both improve their plan and their execution. So make sure that you help your clients remain honest and outcome-based in their approach.

Here’s an example of how we can be psychologically dishonest with ourselves, regardless of our intent. Figure 0.3 below illustrates a research study in which researchers compared how many servings of each of the major food groups study participants thought they had eaten each day and how many servings of the major food groups they actually ate. The chart shows the differences between perceived versus actual intake. In every age group people reported their intake incorrectly. Their perceptions do not always reflect reality.

As you can see, both men and women of all ages ate more grains, fats, oils, and sweets than they thought they had eaten. They also consumed fewer fruits and vegetables and less milk and meat than they thought. In other words, they ate more carbohydrates, fat, and junk food than they thought, while eating less protein and fewer fruits/vegetables than they thought.

Performance

Bodycomposition

Health

FIGURE 0.2the RelAtIoNshIP BetWeeN BoDy ComPosItIoN, heAlth, AND PeRfoRmANCe


123456

123456

123456

123456

123456

123456

-4

WOMEN19-24

1. Grains2. Other (fats, oils & sweets)3. Fruits

4. Vegetables5. Milk6. Meat, etc.

25-50

51+

MEN19-24

25-50

51+

-3 -2 -1 0 1 2 3 4Difference between

serving sizes

I doubt these people were trying to be dishonest with their food records. Rather, this study points out a common problem: People simply don’t have a good idea of what their dietary intake really looks like unless they measure and record it accurately. This is an important lesson for you as their personal trainer. If you’re going to help a client improve their nutrition, you have to provide them with the right tools that will force them to be accurate and honest in their nutritional assessment. (We provide these tools in Unit 2.)

Beyond honesty, good nutrition also requires results. If one of your clients thinks they’re “doing a good job” yet have no results to show for it, how “good” is the job they’re doing? Not very. This is the definition of outcome-based: You evaluate the “goodness” of a client’s nutrition plan by observing what happens once your client follows it. In an outcome-based world, theory is meaningless and results are everything. Your client shouldn’t believe they’re doing a good job based on what they’ve read in the papers or in magazines, what they’ve seen on TV, etc. They can only judge their plan based on the results their diet consistently produces.

Good nutrition equals results.

FIGURE 0.3DIffeReNCe BetWeeN ACtuAl AND PeRCeIveD INtAke of seleCteD fooDs, By sex AND AGe GRouP

sourceUSDA Center for Nutrition Policy and Promotion. Consumption of food group servings: people’s perceptions vs. reality. Nutrition Insight 2000 October; 20


how you can help clients improve their nutritionNow that you know what good nutrition is, you’ll likely be asked to help clients make nutritional changes. After all, as a trainer, you occupy an important role within the health care industry and accordingly, have a large set of responsibilities.

For starters, you’re likely the primary health, body composition, and performance access point for your clients. They may not regularly see a physician or other health care provider to get information on these subjects. Or, if they do, their health care provider(s) may not be equipped to dispense practical advice for preventive health measures, body composition change, or performance improvement. As a result, your client will turn to you for answers in each of these domains. If you’re prepared for this, that’s great. If not, your client may seek help elsewhere and both a client and an opportunity may be lost.

You may also become your client’s social support system. Many new, or even long-term, clients won’t have friends and family committed to helping them improve their exercise and nutrition choices. In fact, those around them may be either uninterested or antagonistic to their lifestyle changes. Clients may look to you for support. Although this places a large amount of responsibility on you to act as a trainer, an educator, and a friend/mentor, it also provides you with a real opportunity to help your clients significantly. In gaining a client’s trust this way, the advice and support you give can quite literally change their lives.

Here are two things that will help you prepare for this responsibility.

keeP uP to DAteAs a trainer, prepare to meet your clients’ need for reliable, current information about exercise, nutrition, supplements, and health in general. While it’s impossible to have a high level of specialized knowledge in each area, luckily that’s not required; a working knowledge should be sufficient.

estABlIsh A NetWoRkEstablish relationships with other healthcare professionals such as registered dietitians, nurses, physical therapists, chiropractors, physicians, etc. By networking and creating a cross-referral system, you’ll not only expand your business network, you’ll have experts to turn to when you just don’t know the answers to certain questions.

your scope of practiceTrainers are often unsure about what they can and can’t talk about with clients. As a qualified trainer, you likely possess a fundamental knowledge of human anatomy and physiology. You’ve committed yourself to helping clients improve their health, body composition, and performance. Your experience tells you that nutrition and training go hand-in-hand, and that results come only when both are improved. Thus, you’ll probably want to talk about both areas with your clients. Yet employers, dietitians, and other health care practitioners may have discouraged you from discussing nutrition’s relationship to your clients’ goals. Perhaps you’ve even been told that it’s illegal to discuss nutrition with clients. Well, that’s not exactly the case.

Although each state and province in North America has different rules for dispensing nutrition advice, in most states it’s well within the scope of practice for personal trainers who possess fundamental nutrition knowledge to address questions and concerns their clients may have. Notice I emphasize the “fundamental knowledge” part. With specific training,

soCIAl suPPoRtNetwork of individuals that provides positive feedback, constructive criticism, and encouragement for one’s lifestyle choices


such as that provided in this course, you’ll possess that fundamental knowledge and be able to discuss nutrition with clients.

However, while technically, in many North American states and provinces, anyone can make general nutritional suggestions, offering specific advice in the form of medical nutrition therapy (i.e., prescribing nutrition for a variety of health conditions and illnesses) is another story. For example, certain states (see Table 0.4 below) have statutes that explicitly define the scope of practice. In these states, performance of the profession of medical nutrition therapy is illegal without first obtaining appropriate dietitian credentials and then applying for a license from the state. In these states it’s perfectly legal for you to make nutritional suggestions for healthy, active individuals. It’s also legal for anyone to share nutrition education through materials that originate from a public or well-known entity such as the American Heart Association, the Centers for Disease Control and Prevention, the American College of Nutrition, etc. It’s only illegal to prescribe nutrition for medical conditions unless you’re a licensed dietitian.

Other states have statutes that limit the use of titles such as “licensed dietitian,” “certified dietitian” or “certified nutritionist.” Yet these states do not necessarily limit the practice of making nutritional prescriptions. In these states, the laws are more liberal, allowing for those without dietetics licensure to offer specific nutrition recommendations as long as they’re certified in nutrition and registered with the state as certified.

In analyzing these definitions, the differences between “general nutritional suggestions” and specific medical nutrition therapy aren’t always apparent. After all, what’s the difference between a co-worker giving some general tips on weight loss for cholesterol reduction and a personal trainer giving the same tips in between sets of squats? And what’s the difference between recommending certain breakfast foods for general good health in a type II diabetic and recommending the same breakfast foods for controlling blood sugar? In the case of grey areas, each state decides these differences. It’s best to check your own state’s laws, rules, and regulations regarding nutritional recommendations.

Allow me to be candid: It’s unlikely that a trainer will get in trouble for making general nutritional suggestions to otherwise healthy clients. The best trainers, those with nutrition continuing education credits such as those obtained in this course, often make suggestions related to optimal rest, hydration, and food intake as these directly relate to gym performance. These topics usually include: recommending adequate sleep (7-9 hours per night), recommending adequate hydration (6-12 8 oz cups per day), recommending clients eat before a workout (a light meal within an hour or so of training), and recommending that clients ingest adequate post-workout nutrition (usually some protein and carbohydrate nutrition).

Trainers often go beyond these vague basics to make more specific recommendations such as:

• Calorie management strategies such as eating less, eating more filling foods, avoiding calorie-dense drinks and snacks, etc.

• Good food selection strategies such as choosing whole grains over refined ones, choosing complete protein sources, choosing water instead of sweetened drinks, etc.

• Good food timing strategies such as eating in and around the workout, eating breakfast, not eating a large meal right before bed, etc.

• Supplement suggestions/information such as which vitamins, minerals, and other essential nutrients (protein, fat, etc.) may be useful

• Healthy lifestyle choices such as meal options for breakfast, lunch, and dinner; alternative snack suggestions; and planning for upcoming social events

meDICAl NutRItIoN theRAPy (mNt)Nutritional advice intended to treat a variety of conditions and illnesses, the provision of which is the exclusive domain of trained and licensed nutrition professionals


As indicated, in most cases, giving general advice on these topics is acceptable. However, it’s also important to recognize that there are many nutritional issues that require medical nutrition therapy and are thus beyond the scope of a trainer’s practice, and against the regulations of many states. This includes, for example, giving nutrition advice for health problems such as diabetes, heart disease, liver dysfunction, kidney stones, etc., as well as giving advice for eating disorders such as anorexia and bulimia.

Every trainer should know when and how to refer a client to an appropriate health professional, and to whom they should refer. I suggest developing a relationship with a high quality local nutrition partner (such as a dietitian also certified in sport nutrition) to create a cross referral system you can turn to when necessary.

Thus, what you discuss with clients will likely depend on the following:

1. your particular state or province’s regulations: Most states allow you to address client questions and concerns about basic nutrition, although different states have different regulations.

2. your client’s likelihood of working with both you and a nutritionist: If your client has the means to work with both you and a dietitian also trained in sports nutrition, this is likely your best bet as long as you trust this person’s advice. If not, you may want to discuss nutrition with your clients as long as you stay within your scope of practice.

3. your client’s health: If your client has health problems or specific nutrition-related diseases, it’s best to refer him or her to a licensed dietitian also trained in sports nutrition as long as you trust this person’s advice. As a personal trainer, you should never offer medical nutrition therapy.

To find a registered dietitian in your area, visit www.eatright.org. To find a sports dietitian in your area, visit www.scandpg.org. To find a sports specific nutritionist, go to www.theissn.org.

nutritional practice regulations, by state

stAtes RequIRING foRmAl CeRtIfICAtIoN AND lICeNse stAtes lImItING tItles But Not the PRACtICe

foR meDICAl NutRItIoN theRAPy of NutRItIoNAl PResCRIPtIoN

tABle 0.4

alabama

alaska

arkansas

california

district of columbia

florida

Georgia

idaho

illinois

iowa

Kansas

Kentucky

louisiana

Maine

Maryland

Massachusetts

Minnesota

Mississippi

Montana

nebraska

new Hampshire

new Mexico

north carolina

north dakota

ohio

oklahoma

Pennsylvania

rhode island

south dakota

Tennessee

Texas

west Virginia

connecticut

delaware

Hawaii

indiana

nevada

new York

oregon

utah

Vermont

Virginia

washington

wisconsin

CRoss-RefeRRAl systemSystem in which two health and fitness professionals (such as a physician or personal trainer) actively recommend each other’s complementary services to their own clients and patients


Applying nutrition technologiesAlthough most trainers that dispense nutrition suggestions do so in and around workout sessions, this is never the ideal time to talk about nutrition. Can you imagine trying to listen to, process, and absorb new information before, during, or after a tough workout? Definitely not the best learning environment, is it? Yet even good trainers often make this mistake.

A better model for making nutritional suggestions is the one that nutrition professionals use, which is the one you’ll learn more about in this course. This systematic coaching process involves discussing nutrition when clients are most receptive to learning, during separate nutrition sessions – which, of course, you can bill for as if they were regular training sessions. During these sessions the client will be ready to share and receive nutritional information.

The 8 steps outlined below represent a logical system of interacting with clients from preparation for the first meeting to continuing education/support. They help systematize the coaching process so that every client gets the attention, education, and support they deserve. During this course, you’ll learn about each step and be provided with tools that ensure a successful coaching environment. We’ll explore each step in greater depth in Unit 2.

The purpose of this courseThis course will help you dispel common myths and fallacies associated with nutrition. It will prepare you to discuss nutrition with your clients by establishing the knowledge base necessary to make general nutritional recommendations that support healthy eating behaviours in your clients. Along with providing nutritional theory and science, we’ll walk you step-by-step through the actual process that sports nutrition practitioners use to prepare for, evaluate, and make recommendations for clients. Each step is accompanied by the sub-steps, descriptions, tables, and summary charts required to implement that step. You should finish this course with both a better understanding of exercise nutrition and with a complete understanding of the tools used in systematically delivering detailed nutritional recommendations.

It is important to note, however, that successful completion of the course examination will not qualify you as a registered dietitian, licensed dietitian, or licensed nutritionist. (Each state has individual rules and regulations about nutrition licensure; check with your particular state

8 steps to effective nutrition coaching

steP 1 Prepare for the client

steP 2 Collect preliminary client information

steP 3 Evaluate client information and explain what it means

steP 4 offer nutritional suggestions and provide nutrition plan

steP 5 offer nutritional supplement suggestions

steP 6 Set behavior goals and create monitoring strategies

steP 7 Make nutritional adjustments based on client results

steP 8 Provide continuing education and support


to ensure you are following legal protocol.) Nor will this course allow you to provide medical nutrition therapy. Instead, this course will provide you with continuing education in the field of nutrition. It will enhance your credibility and your skill set. And it will help you overcome the biggest limiting factor your clients face every day: poor nutrition.

Many clients come to me with “diet experience.” Some have followed lower-carbohydrate diets (similar to the Atkins Diet). others have followed low-fat diets (similar to the ornish Diet). And others have followed more “balanced” plans (similar to the Zone Diet). one client followed all three plans at one point or another and, in conjunction with exercise, achieved similar weight loss results with each of them! Unfortunately, despite the divergent diet philosophies and consistent weight loss, his end result was always the same: he regained all of the weight lost (and then some) before trying the next diet.

in his case, following three wildly different plans resulted in similar weight loss. Some people would ask, “how can this be?” i would ask, “Are these plans so different after all?” instead of focusing on the differences between three strategies that achieve the same result, it’s more important to focus on the similarities. indeed, perhaps the differences aren’t all that important (despite what the diet authors fill their books with) and the results lie in the similarities.

The most important similarity and the reason why my client above got results with a low-carb diet, a low-fat diet, and a balanced macronutrient diet, is this: all three plans forced him to follow the first rule of good nutrition. All three plans, in conjunction with his exercise plan, forced him to control his energy balance. you might recall that it takes a negative energy balance to achieve weight loss. if someone achieves successful weight loss with each of these plans discussed here, it must be the negative energy balance that’s caused the weight loss, not the lack of carbohydrates or the reduction of fat or a specific macronutrient ratio.

how do all three plans create a negative energy balance? Three reasons:

1. The process of following a weight loss plan itself tends to reduce calorie intake, helping decrease “energy in” and helping to shift the body toward a more negative energy balance.

2. The exercise program contributes to the negative energy balance by increasing “energy out.”

3. The Atkins and ornish plans require dieters to restrict their intake of either dietary carbohydrate or dietary fat. The Zone plan prescribes specific ratios of these macronutrients – ratios which lead to eating less total food. is it any wonder that by asking dieters to restrict their intake of something, whether it’s carbohydrates or fat or the ratio of carbohydrates to fat, they’ll end up eating less, again reducing their “energy in”?

i hope it’s now evident why my client had weight loss success with the Atkins, ornish, and Zone plans. it was the negative energy balance that led to his short-term results, not some magical macronutrient mix.

however, all three experiments ultimately failed. This client had rebound weight-gain each time, which was a result of several non-food-related limiting factors. After giving up, he got off track, stopped exercising, and started eating poorly again. however, it wasn’t the food that caused this – it was a host of lifestyle problems that triggered the relapse. only when these factors were addressed while working with my team did he change his fundamental habits and lose his excess body fat for good.

CAse stuDy


summARy1. The best trainers are characterized by their ability to find limiting factors in their

client’s progress and eliminate them.

2. The most significant limiting factor for most clients is their nutritional intake.

3. Good nutrition:

a. controls energy balance;

b. improves nutrient density;

c. achieves the interlocking goals of good health, improved performance, and optimal body composition; and

d. uses honesty and outcome-based evaluation.

4. as a front-line health service provider, you may have to fulfill many roles for your clients including the role of trainer, health information provider, and social support network. with this comes great responsibility but also a great opportunity to change your client’s lives.

5. The trainer’s scope of practice does not include dispensing nutritional prescriptions for specific health conditions, especially medical nutrition therapy, yet most clients expect trainers to help with their eating plan. it’s up to you and your state/provincial regulatory board to decide just how much information you can provide.

6. establish partnerships with high-quality local nutrition partners (dietitians also certified in sport nutrition) to refer clients to when necessary. ensure that these partners follow a systematic nutrition approach, such as the one outlined in this course.

7. when using nutrition technologies, you should follow a specific process that is based on a logical workflow and timeline. This process will be taught in this course.

8. You will not be a registered/licensed dietitian or nutritionist when you complete this course. However, you will be prepared to address many of the nutritional concerns that your healthy clients have.

1uNIt 1

Nutritional Science

ChAPteR 1

Cell stRuCtuRe & funcTion

Chapter objectives

key terms

The cell

Chapter 1 Summary

1

26 uniT 1 | Chapter 1 cell structure and function

Chapter objectives

in this chapter, you’ll learn your body’s cellular structure,

organization, and function. understanding these structural

and functional relationships will help you develop and

evaluate nutrition plans. Most of our cells’ daily activities

have two very simple purposes: to extract nutrients from

the food that we eat, and to use these nutrients to provide

the raw materials and fuel to keep us alive. at the end

of this chapter, you should have a working knowledge of

how humans are organized, from the organismal level all

the way down to the atomic level. You should be able to

recognize the main organelles located in our cells, what

each organelle is responsible for, and how each organelle

interacts with organic molecules to carry out its most

important functions in the body.

To get the most out of this chapter, pay attention to the

key words as well as the chapter summary. if you do,

you’ll be better able to grasp both the particular terms

you’ll be responsible for knowing, as well as the big

picture of how the body is organized and how it functions

at the cellular level.

KeY teRmsmetabolismhomeostasispathogensproteinsenzymesepithelial tissueconnective tissuemuscle tissuenervous tissueorganellescytoplasmmacronutrientsmicronutrientsphytochemicalspotential energyco-factorshormonesgeneticDNAnucleusgenesgenetic polymorphismsnutrigenomicsdiurnalinsulinplasma membranelipidscholesterolphospholipidshydrophilichydrophobiccytosolmitochondriaoxidizeadenosine triphosphatecristae

mitochondrial densitymitochondrial qualityreactive oxygen species (ROS)free radicalschromosomestranscriptiontranslationendoplasmic reticulum (ER)Golgi apparatusribosomesglycoproteinsribonucleic acids (RNA)cisternaelysosomesvesiclesmicroorganismperoxisomesdetoxifyreceptor-ligand binding complexsignal transductionsecond messengerstransport proteinsfacilitated diffusionactive transportsubstratelock-and-key modelinduced fit modelco-enzymescatalyze

1

27uniT 1 | Chapter 1 cell structure and function

The cellThe way the body functions depends on how each of its cells functions. A 150 pound adult has approximately 100,000,000,000,000 (100 trillion) individual cells, all of which must work together in various ways in order to promote life. Cellular and tissue response, signal conduction throughout the body, tissue growth, cellular and organismal respiration, nutrient digestion, nutrient absorption, fluid secretion, waste excretion, blood and biochemical circulation, and cellular and organismal reproduction all depend on the harmony of these 100 trillion cells. Therefore, the cells of our body must function properly for optimal health, body composition, and performance to occur. Optimal nutrient intake is a cornerstone of proper cellular function. Nutrient deficiencies (or excesses) can disrupt the delicate balance of cellular function, causing decreases in both health and performance.

As cells are the building blocks of life, they are the simplest “organisms” that can have a “life of their own.” However, there are further levels of organization within our cells. These sub-cellular structures and chemicals are responsible for our physiological function and metabolism. You may often hear people talk about “the metabolism”, whether fast or slow. Since every single cellular process contributes to human metabolism, the term “metabolism” thus describes all of the diverse physiological processes (both physical and chemical) that generate life. Functionally speaking, our cells form the foundation of our metabolism and our metabolic rate.

In this chapter we’ll discuss some of the cellular components and reactions that contribute to our human metabolism and our ability to sustain life. However, before going deep into cellular organization, let’s start with the highest level of organization – the organism – and progress through smaller levels until we get down to the cellular level. Next, we’ll get even smaller still, working our way down to the atoms themselves. At the end of this chapter you should have an accurate picture of how everything, from our organs all the way down to our atoms, fits together.

oRGANIsmThe organism is, well, you. It’s a comprehensive unit of tissue structures and chemicals, built to withstand various environments from hot to cold, wet to dry, food-abundant to food-scarce. The human body can reproduce, replace, and repair itself, all to stay alive and to maintain homeostasis: the state of balanced function in the body.

oRGAN systemGoing deeper into our body’s organization, we come to our organ systems. Organ systems are exceptionally intricate and involve numerous organs arranged to perform complex functions such as collecting oxygen, breaking down proteins into amino acids, and neutralizing foreign pathogens. The organ systems found in the human body are as follows:

• Integumentary system: Your skin, hair, nails, sweat glands, and other external structures. This system protects the body from external damage.

• skeletal system: Your bones, tendons, ligaments, and other structures. This system supports the body by providing a rigid structure capable of resistance and movement.

• muscular system: Your skeletal muscles, cardiac muscles, and smooth muscles. These muscles are part of your arteries and veins, bladder, gastrointestinal tract, respiratory tract, and more. They produce movement, whether it’s to move you across the room, to move your blood through blood vessels, or to move food through your intestines.

metABolIsmSum of reactions that take place to build up and break down the body

homeostAsIsThe body’s ability to maintain a stable and constant internal condition

PRoteINLarge and complex molecule consisting of amino acids (which contain nitrogen) that are essential for living cells

PAthoGeNDisease-causing agent; usually bacteria, virus, or fungi


• Nervous system: Your brain as well as your nervous tissues. This system is responsible for electrochemical cellular communication and sends signals that trigger thought, movement, voluntary, and involuntary activity.

• endocrine system: Your hormonal organs and glands, including the hypothalamus, pineal gland, pituitary gland, thyroid gland, liver, pancreas, kidney, adrenal gland, testes, ovaries, and more. This system is responsible for chemical cellular communication within the body.

• Circulatory system: Your heart, blood, and blood vessels. This system transports hormones, enzymes, nutrients, and other chemicals throughout the body.

• Immune system: Your thymus, lymph nodes, spleen, tonsils, and other similar organs. This system protects against pathogens, tumor cells, and other foreign invaders.

• Respiratory system: Your nasal cavity, trachea, lungs, and other airways and gas exchange organs. This system excretes carbon dioxide and brings in oxygen.

• Digestive system: Your oral cavity, esophagus, stomach, intestines, and the organs associated with digestion including the liver, gallbladder, pancreas, etc. This system breaks down and absorbs nutrients from food and drink.

• urinary system: Your kidneys, ureters, bladder, urethra, and related organs and glands. This system produces, stores, and eliminates urine.

• Reproductive system: Your sex organs and glands. This system is responsible for human reproduction.

eNZymeSubstance that helps catalyze chemical reactions

Organism (You) Organ systems Organs Tissues Cells Organelle Chemical

Group of differentorgans working

together.

Made up ofdifferenttissues.

Formed bysimilar

cell types.

Consists ofmany

organelles.

Made up ofdifferent

chemicals.

Made up of differentorgan systems.

FIGURE 1.1stRuCtuRAl levels of oRGANIZAtIoN IN the BoDy


oRGANsOur organ systems are made up of individual organs, which perform specialized functions such as hormone manufacture, storage and release, building up or breaking down various chemicals, and more.

tIssuesCollectively, our tissues make up our organs. There are four major types of tissues: epithelial, connective, muscle and nervous. epithelial tissues make up our skin; connective tissues make up structures such as our joints and fascia; our muscle tissues make up our skeletal muscles and heart, and are part of several other organ systems; and our nervous tissues make up our brain, nerves, and associated structures. Our tissues meet a host of the body’s diverse structural and functional needs, such as forming protective barriers against outside invaders (epithelial tissues), moving the body through space (skeletal muscle tissues), and communication between cells (nervous tissues).

CellsOur tissues are made up of large groups of cells, which are the smallest and most abundant structural units in the body. A cell’s size can range from 7.5 micrometres to 300 micrometres. (To give you some perspective, the dot over this letter “i” is about 100 micrometres.) Cells reveal the uniqueness of all living matter in their diverse functions and structures. For example, immune cells have the power to engulf pathogens and destroy them, while muscle cells have sliding filaments that cause muscle contraction and relaxation.

oRGANellesWithin each cell are a number of organelles, collections of molecules/chemicals that perform specific individual functions, very much like position players on a sports team. There are over 24 known organelles, the most important of which will be discussed in this chapter. Examples of organelles include the endoplasmic reticulum (ER), Golgi apparatus, and mitochondrion.

ChemICAlsWithin the cells, there’s a semi-fluid matrix called the cytoplasm, which is composed of a number of chemicals built from structures of varying sizes, from atoms (smallest) to molecules to macromolecules (largest). Macromolecules are made up of groupings of molecules. Molecules are made up of tiny particles called atoms. And these atoms, which are invisible to the naked eye, compose all material things of the universe.

The body is a highly organized entity designed to live and move comfortably within diverse conditions and environments. However, its ability to do so relies heavily on the function of our cells; in particular, the ability of certain organelles to send and receive messages as well as the ability of these organelles to create proteins.

Indeed, nearly everything that happens in the body is based on the production of proteins and the function of the proteins that are produced. Think of the body as a manufacturing plant – that also manufactures itself. The proteins we make end up not only breaking down and rebuilding the plant itself; they break down and rebuild the machines, the workers, the messengers, and more. We’ll get more into this idea as this chapter progresses. For now, just remember that every level of human organization depends on the health of important sub-units – our cells – and the proteins that they make.

oRGANelleComponent of the cell that is responsible for a specific task

CytoPlAsmFluid medium inside of the cell, but outside of the nucleus, that surrounds organelles

ePIthelIAl tIssueTissue composed of cellular layers that protect outer surfaces of the human body such as skin, mucosa, and intestinal lining

CoNNeCtIve tIssueSupportive tissue, such as ligaments, tendons, and fascia, formed from a fibrous matrix

musCle tIssueTissue consisting of bundles of cells that contract when stimulated

NeRvous tIssueTissue capable of conducting impulses that help to connect and communicate signals to other parts of the body


NutRItIoN AND CellulAR INteRACtIoNIn general, the macronutrients (proteins, carbohydrates, and fats), micronutrients (vitamins and minerals), and phytochemicals (from the Greek phyto, or plants – thus, plant chemicals) we eat are broken down from our food through the digestive process into smaller, more distinct sub-units such as amino acids, glucose, fatty acids, etc. These digested and absorbed foodstuffs then travel through our bloodstream to interact with our cells.

These nutrients are taken up into our cells in particular ways to act in a host of life-giving roles.

1. They provide potential energy that’s later released by breaking the chemical bonds between the macronutrients.

2. They can provide raw materials that can then be incorporated into our body structures, including tissues and organs.

3. They can act as co-factors for chemical reactions in the body. All of the chemical reactions that take place in the body require the help of specific proteins, called enzymes. These enzymes often use nutrients gathered from the food we eat to carry out their function.

4. They stimulate the release of hormones, which act as chemical messengers, directing overall body function with their unique messages.

Because of these various and important roles that nutrients have, the food we eat can thus influence our physiological functioning as well as our overall health, body composition, and performance. No wonder nutrition is so critical!

Not everyone responds the same way to the digestion and absorption of specific foods – or to the uptake of specific nutrients into the cell. Recent nutritional research suggests that although the basic mechanics are the same, there are important and intriguing individual differences, which are likely due to our unique genetic makeups. Each cell in our bodies houses our genetic code, a series of proteins called DNA, in an organelle called the nucleus. This code, which is unique to each of us, provides cellular instruction for making proteins. And, as discussed above, these proteins are necessary for our structure and function. As we all have slightly different genetic profiles, the proteins we make may also differ; these variations are responsible for our individual responses to the food we eat.

FIGURE 1.2DNA INsIDe the NuCleus

Co-fACtoRNon-protein compound that interacts with another substance to facilitate a transformation

hoRmoNesCompound created by one cell that travels to and stimulates another cell

Cell nucleus contains chromosomes. Chromosomes contain DNA. DNA provides cellular instructionfor making proteins.

mACRoNutRIeNtNutrient the body requires in large amounts (i.e., protein, fat, carbohydrates)

mICRoNutRIeNtOrganic compound the body requires in very small amounts (i.e., vitamins and minerals)

PhytoChemICAlChemical substance obtained from plants that is biologically active but non-nutritive

PoteNtIAl eNeRGyEnergy stored within a physical system


In general, these differences are quite small. All humans share over 99.9% of the same genes. You may have even heard that humans and chimpanzees share between 95% and 98% similarity in their DNA, which is also true. As a result, physiological functioning between individuals is surprisingly uniform. We are much more alike than we are different. However, these small genetic differences, called genetic polymorphisms, explain why some people respond slightly differently to various types of dietary intakes. These differences may also explain why many areas of nutrition research find apparently conflicting things.

For example, we all have a gene in our livers that makes a specific enzyme necessary to break down caffeine. However, due to these small genetic differences, some of us have the enzyme that breaks down caffeine quickly, while others have the enzyme that breaks down caffeine slowly. People with the fast enzyme see an improvement in health when they drink 1-3 cups of coffee a day. In their bodies, the caffeine is processed and removed quickly while the antioxidants found in coffee can stick around and help protect against free radicals. However, people with the slow enzyme are more likely to experience health problems with the same 1-3 cups of coffee each day. When caffeine is allowed to remain in the body for longer periods of time, it can become unhealthy.

Not only are there individual differences in response to the same foods, different foods possess specific nutrients and other bioactive components that can actually change the message expressed by our unique genes. For example, broccoli contains compounds (isothiocyanates) that can switch on a specific gene in the liver that detoxifies cancer-causing chemicals and other toxins. Without the broccoli, this gene remains inactive and our bodies look for other detoxifiers. With the broccoli, this gene is upregulated and participates more actively in the detoxification process.

Another example is cooked tomatoes. Cooked tomatoes contain compounds (lycopenes) that switch off growth-promoting genes in the prostate. With cooked tomatoes in the diet, prostate cancer risk decreases; without the tomatoes, risk increases.

Fish oil is yet another example. Fish oil (specifically DHA – a fatty acid found in fish oil) signals genes in the brain to produce a chemical that keeps Alzheimer’s disease at bay. People who take fish oil have better cognitive function as they age, relative to those who don’t take fish oil.

There are many examples like these of how nutrition can influence our gene expression to promote or degrade health. However, this area of research goes a bit beyond the scope of this certification course. If you’re interested in this emerging area of research (called nutrigenomics), check out our supplemental reading section in the Appendix.

Nutrient intake is also important in the regulation of our diurnal (daily) physiology. Things like insulin release, glucose uptake, blood glucose, glucagon release, satiety hormones, enzyme release, nutrient transport, protein synthesis, excretion, and elimination are just a few of the cellular responses altered by food intake. Needless to say, there is an important relationship between what we eat and how our cells function. Throughout this course, this interaction will become clearer. By the end of this course, you should have a better grasp of how to optimize health, body composition, and performance by controlling nutrient intake. However, before we talk more about food, let’s discuss the cell in depth, and in particular, the main cellular components and organelles.

GeNetICsSpecific, inherited DNA of an organism, which influences what they become, although environment also plays a key role in the expression of an organism’s genetic code

DNANucleic acids that contain instructions for heredity

NuCleusOrganelle where genetic material is housed

GeNeA particular sequence in DNA or RNA that controls the expression of a protein, and by extension influences the characteristics of an organism

GeNetIC PolymoRPhIsmVariation in the form of one or a sequence of genes

NutRIGeNomICsStudy of how genes respond to nutritional intake

DIuRNAlDaily cycle, e.g., of hormone release

INsulINProtein hormone released from the pancreas; necessary for the metabolism of nutrients


CellulAR ComPoNeNtsTo better understand how the food we eat interacts with our bodies, it’s important to learn about the structures, chemicals, and organelles that reside within each of our cells. In this chapter, we’ll review the following important organelles:

Nucleus

Endoplasmicreticulum

Peroxisome

Lysosome

Mitochondria

Cytoplasm

Golgi apparatus

Plasmamembrane

FIGURE 1.3Cell stRuCtuRe AND oRGANelles

PlAsmA memBRANeLipid bilayer that is permeable to certain compounds that contains the cell

lIPIDOrganic substance that is insoluble in water; provides structure, storage, and messenger functions in the body

CholesteRolLipid/sterol contained in the body’s cells and fluids that acts as a precursor to hormones and bodily structures

Plasma membraneMitochondrionNucleusEndoplasmic reticulum

Golgi apparatusLysosomePeroxisome

These organelles and approximately 17 others (there are about 24 or so in total) give our cells their structure and function, which are in turn often shaped by our nutrient intake.

PlAsmA memBRANeAround the edge of each cell is a boundary, known as the plasma membrane, that separates the cell from its neighbors and from the rest of our body. The plasma membrane’s bilayer (double layer) acts like a protective wall, keeping important chemicals in while keeping harmful chemicals out. The plasma membrane is made up of specific lipids, proteins, cholesterols, and other chemicals and it has an interesting nature: while it forms a structural boundary between the cell and the rest of the body, this boundary is flexible and fluid-like. Membranous organelles – specialized sacs and canals – can float around within the plasma membrane, rather like icebergs floating around in the ocean.

This fluid-like boundary is formed primarily of phospholipids, molecules with phosphate “heads” and fatty acid “tails”. The phosphate “heads” of the lipid molecules that form the bilayer are hydrophilic (water-loving) and therefore can bond to water-based molecules. On the other hand, the fatty acid “tails” of the lipid molecules that form the bilayer are hydrophobic (water-fearing) and bond best with fat-based molecules. This dual-purpose membrane forms a boundary that regulates the free entry of substances into cells.


If a molecule (such as an amino acid, a vitamin, a mineral, or a hormone) wants to enter the cell, it must flow through one of several membrane proteins. These proteins act like gates in a fence, allowing only selected molecules to pass through. These cellular proteins are discussed in more detail later in this chapter.

Because of this lipid structure, the types of fats we consume in our diets will influence the membrane’s fluidity, or flexibility. For example, a diet high in saturated fat makes the membrane more rigid, while a diet high in polyunsaturated fat makes the membrane more fluid. As a more fluid membrane improves the health of most cell types, we need an adequate intake of mono- and polyunsaturated fats as well as a balanced dietary fat profile. This type of intake prevents tight packing of fatty acids in membranes, which allows better hormone and neurotransmitter binding and thus improves cellular communication.

A great example of this is the relationship between membrane fluidity and insulin sensitivity. Recent research has shown that more tightly-packed membranes often have a stronger resistance to insulin, leading to higher insulin concentrations in the blood and increased risk of type II diabetes or diabetes-like symptoms.

CytoPlAsmThe interior space of the cell, composed of a gel-like solution called cytosol, is called the cytoplasm. Many organelles, enzymes, salts and other organic molecules, including stored carbohydrates and fats, are suspended and maintained in the cytoplasm. The body carries out many of its chemical reactions in this gel-like matrix, including most of its enzymatic reactions.

Indeed, this is why the cytosol is rich in stored carbohydrates. As energy is required to do work, these carbohydrates can be broken down quickly and used to transfer energy. Because this process is governed by cytosolic enzymes, the high demand for energy in physically active people typically stimulates an upregulation in the production of these key enzymes, along with both carbohydrate and fat storage. Thus exercise increases both the cellular carbohydrate supply as well as the cell’s ability to break down these carbohydrates to do more work. This is especially true in skeletal muscle cells, since this is where highly trained individuals need most of their energy.

FIGURE 1.4PlAsmA memBRANe

PhosPholIPIDsA type of lipid with a hydrophilic phosphate group “head” and hydrophobic fatty acid “tail” that forms cell membranes

hyDRoPhIlICStrong affinity for water

hyDRoPhoBICLack of affinity for water

CytosolInternal fluid portion of the cell

Extracellular space

Intracellular space

Hydrophilicregion

Hydrophilicregion

Hydrophobicregion

Phospholipid


mItoChoNDRIoNmitochondria (plural of mitochondrion) are highly organized cellular organelles responsible for converting things like protein, carbohydrate, and fat into energy. Much of the energy that’s stored in carbohydrates, proteins, and fats is useless to the body unless it can be oxidized. As it’s oxidized, the energy stored in the chemical bonds is released. And, in the mitochondrion, this energy is converted into adenosine triphosphate or ATP.

Since ATP is the energy currency of the cell, mitochondria are responsible for producing most of the body’s energy – about 95% of it. Thus, mitochondria are critical to overall health and function. Without efficient mitochondria, our ability to live, breathe, move, and be energetic is severely compromised.

ATP generation in the mitochondrion takes place in the inner mitochondrial membrane. The outer membrane of the mitochondrion is porous, while the inner membrane serves as the main barrier between it and the rest of the cell. The inner membrane contains folds called cristae, in which the enzymes and structures responsible for making ATP are embedded.

Since the mitochondria generate power for the cell, the number of mitochondria in a cell is directly related to the activity of the cell. Frequent bouts of exercise can increase the number of mitochondria inside muscle cells. This increase means more total energy production for the muscle. However, if muscle size also grows in proportion to mitochondrial increase, the ATP production per unit muscle may not change. This is why we typically see an increase in mitochondrial density in elite athletes: they not only build more total mitochondria with training, they also build more mitochondra per unit of muscle mass. This helps to supply the oxygen and ATP required for high level endurance performance.

oxIDIZeTo combine with oxygen

ADeNosINe tRIPhosPhAte (AtP)Adenosine molecule with three phosphate groups that supplies energy for the cell

CRIstAeInternal compartments of the mitochondria

mItoChoNDRIAl DeNsItyQuantity of mitochondria per unit volume

Matrix

Inner membranefolded into cristae

Outer membrane

Intermembranespace

FIGURE 1.5mItoChoNDRIoN

mItoChoNDRIAOrganelles that supply the cells’ energy/ATP (singular: mitochondrion)


mitochondrial quality is also linked to health and well-being. During ATP generation, our mitochondria consume a specific amount of oxygen as electrons are passed down what is called the electron transport chain (more on this later). In the past, the relationship between electron transport chain activity and ATP produced was assumed to be fairly constant between individuals. However, new data suggest that different people may make ATP at different rates, even with the same oxygen consumption/electron transport chain activity. This phenomenon may be related to both a lower oxygen requirement (and the related lower food requirement) for the same ATP yield, as well as a lower production of reactive oxygen species (Ros), or free radicals. You see, when oxygen is consumed in the production of ATP, reactive oxygen species are formed. These unstable molecules can cause quite a bit of cellular damage, including some pretty serious DNA damage. So it may be best to keep ROS production under control.

In the past scientists believed that the more oxygen consumed, the more ROS were formed. However, it seems that in those with less efficient mitochondria, more ROS are formed per unit ATP produced. With high efficiency mitochondria, the opposite is true: More ATP is produced per unit oxygen consumed and per ROS formed. This may mean that those with higher mitochondrial efficiency will live longer, perform better athletically, and feel more energetic.

While this research area is in its infancy, it’s interesting to note that the relationship between ATP generation and free radical production relies on mitochondrial quality.

NuCleusThe nucleus is the largest organelle and is located in the central portion of the cell. Typically, each cell has only one nucleus. The nucleus is critical to cellular function, as it’s the residence of DNA, also known as the genetic code. Wrapped up in chromosomes, our DNA dictates which proteins are formed in the body, which ultimately determines everything from how the body develops, to how it repairs itself, to how it transports and/or metabolizes every chemical introduced into circulation.

As discussed earlier, there is an important link between our DNA, our food intake, and our health. In fact, much of what we eat interacts directly with our DNA or causes hormonal cascades that influence our DNA. These relationships begin in our nucleus as specific chemicals can bond with our DNA to initiate cellular protein-making, called transcription and translation.

eR AND GolGI APPARAtusThe endoplasmic reticulum, or ER, is a “circulatory” network located inside the cytoplasm and adjacent to the nucleus. Once our DNA sends out a signal to make proteins, the ER and Golgi apparatus receive this genetic message from the DNA and make and transport the required proteins for use inside and outside the cell.

There are two types of ER: smooth and rough. Rough ER is lined with ribosomes, which give it its “rough” appearance. These ribosomes are the sites of protein synthesis and are therefore considered “protein factories” of the cell. Smooth ER, on the other hand, does not have ribosomes; therefore it doesn’t directly form proteins. Rather, it synthesizes lipids, steroid hormones, and carbohydrates to use in glycoproteins.

The synthesis of proteins takes place using ribonucleic acids (RNA) and although the specific steps of protein production are beyond the scope of this manual, it’s important to know that once these proteins are synthesized in the ribosomes of the rough ER, they move towards the Golgi apparatus, another organelle that is mostly responsible for preparing the newly formed protein molecules that are destined to leave the cell. The Golgi apparatus contains cisternae (tiny disc-like “holding tanks”, similar to the word “cistern”) that are stacked on one another

mItoChoNDRIAl quAlItySpecific attributes of mitochondria

ReACtIve oxyGeN sPeCIes (Ros)Various substances formed as a byproduct of metabolism that are highly reactive due to the unpaired electron shell

fRee RADICAlsReactive atom with one or more electrons

ChRomosomesOrganized structure of DNA, found within cells, that contains the genes of an organism

tRANsCRIPtIoNConstruction of mRNA from a DNA molecule

tRANslAtIoNForming a protein molecule based on the information contained in the mRNA

eNDoPlAsmIC RetICulumCytoplasmic membrane that translates proteins

GolGI APPARAtusCytoplasmic organelle necessary for the modification and transport of proteins

RIBosomesA complex rich in RNA and protein found in cells

GlyCoPRoteINsProtein that contains a carbohydrate group, involved in membrane integrity

RIBoNuCleIC ACIDs (RNA)Various nucleic acids on a single strand containing ribose and uracil, necessary for the control of cell activities

CIsteRNAeFlattened membrane disc of Golgi apparatus (plural: cisternae)


and small, circular vesicles. These vesicles act like little chaperones, engulfing the protein molecules and transporting them to the cell membranes for release or incorporation.

lysosomes AND PeRoxIsomeslysosomes are enzyme-containing vesicles (small sacs), capable of breaking down cellular components and protecting cells. If a large molecule, such as an old cellular structure or a microorganism enters the cell, the lysosome will digest and dispose of it. Basically, lysosomes are considered “cellular garbage disposals” that help in the process of cellular renewal and/or cellular protection.

Peroxisomes are similar to lysosomes: they are small membranous sacs containing enzymes (catalase and oxidase), which also detoxify harmful substances that enter cells. Found commonly in liver and kidney cells, peroxisomes are also important in cholesterol synthesis, bile acid synthesis, ß-oxidation, and prostaglandin metabolism. Interestingly, peroxisomes function in a manner very similar to mitochondria, but there’s one very important difference in how they handle the breakdown of fats. Specifically, when fats are broken down in the peroxisome, 30-40% more heat is produced and 30% less ATP is produced. Since dietary omega-3s, especially fish oils, increase fat breakdown through the peroxisomes, more fat breakdown is required per unit of ATP production. This means that more fat is burned to do the same daily activities.

CellulAR PRoteINsNow that we’ve covered the major cellular organelles, let’s cover the main proteins found in our cells, protein receptors, transport proteins, and enzymes.

Understanding the function of these cellular proteins helps us understand how molecules like nutrients, hormones, and other chemicals can influence our cells’ functions.

PeRoxIsomeCytoplasmic organelle with enzymes for production and breakdown of hydrogen peroxide

DetoxIfyTo remove a poison or toxin from the body

FIGURE 1.6eNDoPlAsmIC RetICulum

C

T

Rough endoplasmicreticulum (ER)

Transport vesiclefrom ER

Golgi apparatus

Transport vesiclefrom Golgi apparatus

Cis (C) face:receives transportvesicles from ER

Trans (T) face: producesvesicles for cellularuse or for excretion

Smooth ER

lysosomeOrganelle containing hydrolytic enzymes

vesIClesFluid filled pouch/sac that can transport and store compounds

mICRooRGANIsmOrganism of microscopic size


PRoteIN ReCePtoRs AND Cell sIGNAlINGOur plasma membranes typically prevent the entry of nutrients, hormones, and so forth from the bloodstream. However, specific proteins embedded in the cell membrane can act as receptors that, when bound to these chemicals, can produce a specific response. Of course, not all receptors and chemicals are destined to fit together. This is a good thing, since specific molecules need to be kept out of specific cells. However, if the chemical and the receptor match, they bind together to form a receptor-ligand binding complex. Once this bond forms successfully, a process called signal transduction can take place. second messengers are turned on and either direct cellular responses occur, or changes in gene expression take place in the nucleus of our cells.

An example of a protein receptor initiating a signal transduction cascade is the cellular response to insulin. Whenever we eat a meal, especially one higher in carbohydrate, the hormone insulin is released from the pancreas. This hormone then travels through the bloodstream and binds to a specific protein receptor in one of our cell membranes. This ligand then alters cellular function, in particular the cell’s carbohydrate uptake, by upregulating the number and operation of protein molecules within the cell that bring glucose into the cell.

While a host of protein receptors are located within the cell membrane, additional receptors are located inside our cells. When bound to different nutrients, hormones, and so on, these receptors can also alter cellular function.

tRANsPoRt PRoteINstransport proteins are proteins in the cell membrane that act as channels or molecular carriers. Unlike receptor proteins, these proteins allow the passage of water-soluble molecules between the spaces inside the cells and the spaces outside the cells. This

ReCePtoR-lIGAND BINDING ComPlexA complex formed between a receptor and a substance to allow for further cellular activity

sIGNAl tRANsDuCtIoNConversion of one signal to another by a cell

seCoND messeNGeRSubstance that mediates intracellular activity by relaying a signal from an extracellular molecule

tRANsPoRt PRoteINProtein that moves compounds across a membrane

fACIlItAteD DIffusIoNTransport that requires a carrier molecule; occurs when diffusion of a substance on its own is not possible

ACtIve tRANsPoRtMovement of particles from an area of low concentration to an area of high concentration; requires energy and enzymes

CYTOSOL

NUCLEUS

Receptor1. Receptor-ligand binding

Ligand(primarymessenger)

Secondmessenger

3. Cellular responses

4. Changes ingene expression

2. Signaltransduction(via secondmessengers)

FIGURE 1.7PRoteIN ReCePtoR AND CellulAR sIGNAlING


movement across the plasma membrane can take place via one of two mechanisms: facilitated diffusion or active transport.

This type of cellular transport allows necessary molecules, such as vitamins, minerals, glucose, and amino acids into the cells, where they can perform vital functions.

eNZymesEnzymes make up the largest group of proteins in the body. You can often spot enzymes by their names, which typically end in “-ase”, such as lipase (enzymes that degrade lipids), protease (enzymes that degrade proteins), and amylase (enzymes that degrade carbohydrates). Enzymes are important biological catalysts that facilitate and speed up nearly every chemical reaction that occurs in the body. A host of environmental, genetic, and nutritional factors – including temperature, pH, substrate concentration, and vitamin and mineral status – can influence enzymatic function. Thus nutrition plays an important role in most enzymatic reactions.

Enzymes work by exposing their own “active sites” to connect with specific molecules. Once the enzyme can hold these molecules in place, reactions can occur. One model of this process is the lock-and-key model. In this model, the enzyme and chemical substrate fit together tightly and carry out their reaction. In another model, the induced fit model, the enzyme and chemical substrate undergo structural changes when close to one another, eventually fitting together properly and initiating the catalytic reaction.

Just like a copilot operates alongside a pilot, co-enzymes operate alongside of enzymes. Co-enzymes are non-protein molecules, composed wholly or partly of vitamins, and are necessary to assist in enzyme catalyzed reactions.

FIGURE 1.8 tRANsPoRt PRoteINs

loCk-AND-key moDelModel that explains enzyme specificity

suBstRAteSubstance acted upon by an enzyme

INDuCeD fIt moDelModel that suggests enzymes are rather flexible structures

Co-eNZymeNon-protein compound that forms the active portion of an enzyme system

CAtAlyZeInitiate or increase the rate of a chemical reaction

Extracellular space

Intracellular space


products

enzyme

enzyme-substrate

enzyme

substrate

bonds in substrateare weakened

activesite

FIGURE 1.9 eNZymes

This chapter has provided an introduction to the basic cellular anatomy and function that you’ll need to understand the body’s organization as well as its interaction with food and nutrients. This foundational knowledge is critical to your development as a nutritional thinker, and it will enable you to fully comprehend the applied nutritional information that we’ll be sharing with you as this course progresses. Make sure you’re comfortable with the information contained in this chapter before moving on to the next and beyond.


summARy1. The trillions of cells of the human body work together to form tissues, organs, and

organ systems. The total of all of the activities taking place in these systems is what most people refer to as “metabolism.”

2. There are many levels of organization in the body, from microscopic atoms up to fully functional organisms. each level is necessary for optimal functioning of the next.

3. The food we eat interacts with the small chemical reactions and processes taking place in our cells. This interaction, especially with our genetic material, determines our health.

4. food affects our health in four ways: it provides energy; it provides metabolic co-factors; it’s incorporated into body structures; and it influences chemicals such as hormones and neurotransmitters.

5. our organelles, which reside within our cells, convert food into aTP and make proteins.

6. our genetic information directs protein-making signals. our food can affect these signals as well as the quality of the proteins that are made.

7. enzymes and co-enzymes are compounds necessary for nearly every cellular process in the body. enzymes help reactions occur.

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Precision Nutrition Certificaiton Textbook Table of Contents, Introduction and Chapter 1

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