Nutrition and Exercise ScienceNutrition and Exercise Science

IntroductionIntroduction

Optimal genetic endowment, optimal training Optimal genetic endowment, optimal training and a suitable socioeconomic environment are and a suitable socioeconomic environment are three keys to success in physical activitythree keys to success in physical activityWhen athletes attain an elite level within their When athletes attain an elite level within their sport, they tend to be very homogeneous in sport, they tend to be very homogeneous in terms of genetics, training and environmentterms of genetics, training and environmentIt is becoming increasingly clear that It is becoming increasingly clear that nutritional practice can either hamper or nutritional practice can either hamper or improve an athlete’s performanceimprove an athlete’s performance

The energy value of foodThe energy value of food

Calories equals the amount of heat required to Calories equals the amount of heat required to raise the temperature of 1g water from 14.5 to raise the temperature of 1g water from 14.5 to 15.5 ℃15.5 ℃

CHO and protein release about 4 kcal/gCHO and protein release about 4 kcal/g

Fats release more than 9 kcal/gFats release more than 9 kcal/g

Nutrition FactsNutrition Facts

Nutritional label allows Nutritional label allows us to determine the us to determine the relative proportions of relative proportions of fat, protein, and fat, protein, and carbohydrate in each carbohydrate in each servingserving

Components of the Athletes’ DietComponents of the Athletes’ Diet

Daily food intake should Daily food intake should include about include about – CHO : 55%-70%CHO : 55%-70%

– Protein : 12%-15%Protein : 12%-15%

– Fat : 20%-30%Fat : 20%-30%

Carbohydrate (CHO)Carbohydrate (CHO)

CHO is the primary fuel for certain forms of exerciseCHO is the primary fuel for certain forms of exerciseIs the most readily available fuelsIs the most readily available fuelsDietary CHO comes in two formsDietary CHO comes in two forms– StarchStarch– SugarSugar

Glucose is stored in the body as the complex CHO Glucose is stored in the body as the complex CHO called glycogencalled glycogenLiver glycogen maintains blood glucose levelLiver glycogen maintains blood glucose levelMuscle glycogen does not provide glucose to Muscle glycogen does not provide glucose to bloodstream and serves as one of the preferred fuel bloodstream and serves as one of the preferred fuel sources for energy by the musclesources for energy by the muscle

Glycogen

Blood Glucose ControlBlood Glucose Control

Influence of Exercise Intensity on Influence of Exercise Intensity on Muscle Fuel SourceMuscle Fuel Source

Effect of Exercise Duration on Muscle Effect of Exercise Duration on Muscle Fuel SourceFuel Source

How much Carbohydrate is How much Carbohydrate is EnoughEnough

Eat 55% to 70% total Eat 55% to 70% total calories from CHO, that calories from CHO, that is about 5-10g CHO/kg is about 5-10g CHO/kg body weight per daybody weight per day

Relative levels of Relative levels of protein, CHO, fat protein, CHO, fat required depends on the required depends on the duration and intensity of duration and intensity of exerciseexercise

How much Carbohydrate is EnoughHow much Carbohydrate is Enough

Consumption of a large Consumption of a large quantity of CHO quantity of CHO between exercise between exercise sessions can help sessions can help maintain muscle maintain muscle glycogen levelsglycogen levels

This delays fatigue that This delays fatigue that may occur when blood may occur when blood glucose levels drop too glucose levels drop too lowlow

FatsFats

Dietary fat is essential in our dietDietary fat is essential in our diet

A healthy diet contain 20 to 25% fat caloriesA healthy diet contain 20 to 25% fat calories

Athletes who need more than 3500 calories per Athletes who need more than 3500 calories per day to maintain their weight and training must day to maintain their weight and training must be more liberal with fat intakebe more liberal with fat intake

FatsFats

Fuel source selection is Fuel source selection is dependent on the level dependent on the level of aerobic power of aerobic power requiredrequiredAt higher aerobic power At higher aerobic power requirements, the requirements, the sympathetic nervous sympathetic nervous system (SNS) may system (SNS) may provide important provide important hormonal stimulation hormonal stimulation for metabolismfor metabolism

→ Training →

←SNS Stimulation ←

ProteinsProteins

Protein is about 12 to 15% of our daily energy Protein is about 12 to 15% of our daily energy intakeintake

Most of us only use 2 to 5% of this protein to Most of us only use 2 to 5% of this protein to provide energy for activityprovide energy for activity

Remaining protein is used to repair and restore Remaining protein is used to repair and restore tissue on a daily basis, or provide a substrate tissue on a daily basis, or provide a substrate for growth and developmentfor growth and development

ProteinsProteinsIn endurance activities up In endurance activities up to 15% of the energy to 15% of the energy expended during exercise expended during exercise can come from proteincan come from proteinRDA for adults is 0.8g of RDA for adults is 0.8g of protein/kg desirable weightprotein/kg desirable weightAthlete in the initial stages Athlete in the initial stages of resistance-type training of resistance-type training involving a significant rate involving a significant rate of muscle building should of muscle building should consume about 1.5g/kg consume about 1.5g/kg desirable weightdesirable weight

Fluids and HydrationFluids and Hydration

Water makes up 50 to Water makes up 50 to 60% of the body weight60% of the body weight

Water also comprise Water also comprise 83% of blood, 70% of 83% of blood, 70% of muscle, 30% fat, and muscle, 30% fat, and 10% of bone10% of bone

Sources of fluid intake and lossSources of fluid intake and lossWater intakeWater intake

– Drink 1000 mlDrink 1000 ml

– Water content in food Water content in food 1000 ml1000 ml

– Water produced from Water produced from metabolism 350 mlmetabolism 350 ml

– Total intake 2350 mlTotal intake 2350 ml

Water outputWater output

– Skin perspiration 500 mlSkin perspiration 500 ml

– Lung respiration 400 mlLung respiration 400 ml

– Urine 1300mlUrine 1300ml

– Colon loss 150 mlColon loss 150 ml

– Total output 2350 mlTotal output 2350 ml

During exercise, the rate of heat production by active During exercise, the rate of heat production by active muscles can be as much as 100 times that of inactive muscles can be as much as 100 times that of inactive musclesmusclesOne g of evaporated water form the skin removes One g of evaporated water form the skin removes about 0.6 calories of heat from the bodyabout 0.6 calories of heat from the bodyFluid replacement is imperative during exercise to Fluid replacement is imperative during exercise to prevent dehydration and its possible catastrophic prevent dehydration and its possible catastrophic consequencesconsequencesA loss of body weight due dehydrationA loss of body weight due dehydration– 1% → thirst1% → thirst– 3% → impaired exercise tolerance3% → impaired exercise tolerance– 5% →impaired heat tolerance5% →impaired heat tolerance

Only 50 to 60% of the fluids lost during exercise can Only 50 to 60% of the fluids lost during exercise can be replenished during exercise be replenished during exercise

Tips for fluid replenishmentTips for fluid replenishment

Intense workout lasting longer than 1 hour in Intense workout lasting longer than 1 hour in high heat and humidity, sport drink may be high heat and humidity, sport drink may be advantageadvantageDrink 2 to 4 cups fluids per 1 hour of exerciseDrink 2 to 4 cups fluids per 1 hour of exerciseKeep the fluids cool if possibleKeep the fluids cool if possibleDrink 4 to 8 ounces each time, This voulme is Drink 4 to 8 ounces each time, This voulme is optimal to stimulate the stomach to contract optimal to stimulate the stomach to contract and empty fluids into the small intestineand empty fluids into the small intestineDrink every 15 min of exerciseDrink every 15 min of exercise

Vitamins and MineralsVitamins and Minerals

Athletes tend to consume many more vitamins Athletes tend to consume many more vitamins (e.g. Vita. B) and minerals along with the (e.g. Vita. B) and minerals along with the caloriescaloriesMinerals tend to be suboptimal in many Minerals tend to be suboptimal in many athletes’ diets, especially the diets of women athletes’ diets, especially the diets of women athletes who have greater iron losses than athletes who have greater iron losses than nonathletes, and this is associated with intense nonathletes, and this is associated with intense trainingtrainingMenopause need 15 to 10 mg iron per dayMenopause need 15 to 10 mg iron per day

Performance EatingPerformance Eating

Optimal performance requires optimal Optimal performance requires optimal nutritionnutrition

The principles are the same whether the The principles are the same whether the athletes is involved in active heavy training or athletes is involved in active heavy training or in competitionin competition

Food Selection Before Performance Food Selection Before Performance

Eat a diet that is 5 to 10 g of CHO/kg body Eat a diet that is 5 to 10 g of CHO/kg body weight will maintain liver and muscle weight will maintain liver and muscle glycogen storesglycogen stores

Events or intense exercise that last more than 2 Events or intense exercise that last more than 2 hours need maximum glycogen stores for hours need maximum glycogen stores for optimal performanceoptimal performance

Never eat foods before an event that have not Never eat foods before an event that have not been tried during training !!been tried during training !!

CHO Loading CHO Loading

Food Selection During PerformanceFood Selection During PerformanceDuring an intense workout or event is to During an intense workout or event is to rehydrate as quickly as possiblerehydrate as quickly as possibleCool water is generally the best choice for Cool water is generally the best choice for fluid replacementfluid replacementSport drinks may be beneficial if events are Sport drinks may be beneficial if events are longer than 1 hour in durationlonger than 1 hour in durationCHO in beverages not only enhances fluid CHO in beverages not only enhances fluid absorption, but also provide CHO to prevent absorption, but also provide CHO to prevent drops in blood glucosedrops in blood glucoseConsuming 0.2 to 0.6 g of CHO/kg body Consuming 0.2 to 0.6 g of CHO/kg body weight per hour of exerciseweight per hour of exerciseUltra-endurance athletes must also consider Ultra-endurance athletes must also consider sodium replacements in events lasting more sodium replacements in events lasting more than 8 hoursthan 8 hours

Food Selection After PerformanceFood Selection After Performance

To recovery quickly To recovery quickly from an intense workout from an intense workout or competition of more or competition of more than 1 hour should than 1 hour should focus on both fluid and focus on both fluid and CHO ingestionCHO ingestionMore effective time to More effective time to replenish glycogen replenish glycogen occurs within the first occurs within the first 45 minutes after a 45 minutes after a strenuous exercise boutstrenuous exercise bout

Energy BalanceEnergy Balance

If body weight is to be If body weight is to be maintained, the amount maintained, the amount of energy we expand a of energy we expand a daily basis must be daily basis must be matched by the amount matched by the amount of energy we consumeof energy we consume

Body CompositionBody Composition

Two compartment Two compartment model in exercise model in exercise scientistscientist– Fat compartment Fat compartment – Fat-free, or lean body Fat-free, or lean body

mass compartmentmass compartment

Adult woman have Adult woman have about 25% of their about 25% of their weight as fat, while men weight as fat, while men have about 15% if their have about 15% if their weight as fatweight as fat

Measuring Body CompositionMeasuring Body Composition

Densitometry, Densitometry, Hydrostatic weightingHydrostatic weighting

Anthropometric Measurement of Body Anthropometric Measurement of Body CompositionComposition

Bioelectrial Impedance AnalysisBioelectrial Impedance AnalysisFat free mass is a good Fat free mass is a good conductor of electrical conductor of electrical current and fat is an current and fat is an excellent insulatorexcellent insulator

Measurement of the Measurement of the body’s conductive body’s conductive properties can be used properties can be used to estimate body to estimate body compositioncomposition

Magnetic Resonance ImagingMagnetic Resonance Imaging

Summary PointsSummary Points

Nutrition is one variable that contributes to Nutrition is one variable that contributes to athletic performance that can easily be athletic performance that can easily be changed using the guidelines providedchanged using the guidelines provided

People who engage in routine intensive People who engage in routine intensive physical training need to be concerned about physical training need to be concerned about caloric intake, food composition, water caloric intake, food composition, water balance, and vitamin and mineral intakebalance, and vitamin and mineral intake

To maintain body weight, energy intake must To maintain body weight, energy intake must meet energy expenditure, it this does not meet energy expenditure, it this does not occur, changes in weight (and ultimately occur, changes in weight (and ultimately performance) will become evidentperformance) will become evident

Carbohydrate intake prior to, during, and after Carbohydrate intake prior to, during, and after a workout bout or competitive event is also a workout bout or competitive event is also import. CHO can clearly be considered true import. CHO can clearly be considered true ergogenic aidsergogenic aids

Small deficits in body water can result in Small deficits in body water can result in dramatic reductions in physical performance. dramatic reductions in physical performance. This decline in performance is due to This decline in performance is due to compromised cardiovascular and compromised cardiovascular and thermoregulatory capacity. Water intake is thermoregulatory capacity. Water intake is critical and must be a conscious priority critical and must be a conscious priority particularly during exercise in the heatparticularly during exercise in the heat

Because of the involvement of vitamins and Because of the involvement of vitamins and minerals as cofactors and components minerals as cofactors and components essential to metabolic pathways, athletes, essential to metabolic pathways, athletes, trainers, and coaches need to be aware of the trainers, and coaches need to be aware of the dietary patterns of their athletesdietary patterns of their athletes

Many athletes make poor food selection choices as a Many athletes make poor food selection choices as a result of lifestyle or ignorance such that their diet result of lifestyle or ignorance such that their diet may be deficient in one or more of these compoundsmay be deficient in one or more of these compounds

Although coaches cannot alter fiber type, heart size, Although coaches cannot alter fiber type, heart size, or limb length, they can influence performance by or limb length, they can influence performance by educating their athletes about proper nutritioneducating their athletes about proper nutrition

In addition to performance benefits, nutrition can also In addition to performance benefits, nutrition can also significantly affect health and wellness such that significantly affect health and wellness such that short-term and long-term benefits may be realizedshort-term and long-term benefits may be realized

DiscussionDiscussion

Can you select two different sports fitting Can you select two different sports fitting nutritional needs to them in order to promote nutritional needs to them in order to promote athletic performancesathletic performances

What do you think about the issue of dietary What do you think about the issue of dietary supplementation to the young athletes supplementation to the young athletes undertaking a hard physical conditioning.undertaking a hard physical conditioning.

What is your opinion of preventing aging by What is your opinion of preventing aging by consuming large quantity of assorted vitamins consuming large quantity of assorted vitamins (e.g. Centrum) daily after fifty.(e.g. Centrum) daily after fifty.