Chapter 9

Weight Management: Overweight, Obesity, and

Underweight

Overweight and Obesity

Major health problem in the U.S.Prevalence continues to increaseDefined by BMI of 25 or greaterEpidemic is worldwide

Fat Cell Development

Energy in exceeds energy out Stored in fat cells of adipose tissue

Body fat Number and size of fat cells

Energy out exceeds energy in Fat cell size decreases; no change in number

Fat Cell Metabolism

Lipoprotein lipase (LPL) activity Storage of triglycerides Obese people vs. lean people Activity in varying body regions

Enzyme activity releasing and breaking down fat

Fat oxidation is not efficient

Causes of Overweight & Obesity – Genetics &

EpigeneticsCausative role of genetics

Genetic influences do seem to be involved

Genetics may determine predisposition to obesity

Human genomeObesity gene

Codes for the protein leptin Locations of leptin secretion

Causes of Overweight & Obesity – Genetics &

EpigeneticsObesity gene

Genetic deficiency of leptin or genetic mutation Leptin resistance Roles in the body

Energy regulation Others

Causes of Overweight & Obesity – Genetics &

EpigeneticsAdiponectin

Secreted by adipose tissue Inverse correlation with body fat Benefits

Ghrelin Promotes positive energy balance Inverse correlation with body weight Roles in the body beyond energy regulation

Causes of Overweight & Obesity – Genetics &

EpigeneticsPYY

GI cells secrete in proportion to kcalories consumed Signals satiety and decreases food intake

Ideal diet Maintain satiating hormones Minimize appetite stimulating hormones Low in fat and rich in fiber

Causes of Overweight & Obesity – Genetics &

EpigeneticsUncoupling proteins

Proteins involved in energy metabolism Two types of fat

White adipose tissue Brown adipose tissue

Uncoupling proteins found in both types of fat Influence basal metabolic rate (BMR)

Causes of Overweight & Obesity – Environment

Encountered daily circumstances Interaction between environment and genetics

Overeating Present and past eating and activity patterns

influence current body weight Availability Serving sizes

Physical inactivity Life requires little exertion Inactivity contributes to weight gain and poor health DRI for prevention of weight gain

Problems of Overweight and Obesity – Health Risks

Three indicators BMI Waist circumference Disease risk profile

Factors taken into account

Beneficial weight loss Health status Motivation

Problems of Overweight and Obesity – Health Risks

Overweight in good health Sometimes health is not the motivation for weight loss

Obese or overweight with risk factors Two or more risk factors

Obese or overweight with life-threatening condition Recommendation to lose weight

Problems of Overweight and Obesity – Perceptions &

PrejudicesMost obese people do not successfully lose

weight and maintain the lossSocial consequences

Jobs, school, and in social situations

Psychological problems

Problems of Overweight and Obesity – Dangerous

InterventionsIntervention dangersDiet books and weight-loss programs

Little success with weight loss maintenance

Fad dietsWeight-loss productsHerbal products

Laws for dietary supplements

Other gimmicks

Aggressive Treatments for Obesity – Drugs

Strategies for weight reduction depend on: Degree of obesity Risk of disease

Use drugs as part of long-term comprehensive weight-loss programs Assist with modest weight loss

Drugs approved by FDA for obesity Sibutramine Orlistat Phentermine and diethylpropion Other drugs

Aggressive Treatments for Obesity – Surgery

Clinically severe obesity 200,000 surgeries performed each year

Reduces food capacity of stomach Effectively limits food intake

Reduce production of ghrelinHealth-related benefitsLong-term safety and effectivenessLiposuction

Weight Loss Strategies

Successful strategies Small changes Moderate losses Reasonable goals

Reasonable rate of weight loss

Benefits of modest weight lossIncorporation of healthy eating and physical

activity

Wt Loss Strategies – Eating Plans

Be realistic about energy intake Provide less energy than is needed Goal: nutritional adequacy without excess Breakfast frequency

Nutritional adequacy Minimum of 1200 kcalories a day

Eat small portions Eat less food at each meal; structured meal

replacement plans Feel satisfied, not stuffed

Lower energy density

Wt Loss Strategies – Eating Plans

Remember water Assistance with weight management

Focus on fiber Low in energy and high in nutrients; require effort to

eat

Choose fats sensibly Energy density and satiation

Select carbohydrates carefully Artificial sweeteners

Watch for empty kcalories Fat, sugar, and alcohol

Wt Loss Strategies – Physical Activity

Best approach to weight management Moderate physical activity plus activities of daily life

Combination of diet and physical activity Lose more fat Retain more muscle Regain less weight

Reduction of abdominal fat

Wt Loss Strategies – Physical Activity

kCalorie expenditure Body weight, intensity, and duration

Greater the energy deficit, greater the fat loss

Discretionary kcalorie allowanceMetabolism

Speeds up with activity Immediate and long-term benefits

Wt Loss Strategies – Physical Activity

Wt Loss Strategies – Physical Activity

Body composition Fat decreases and lean body mass increases Strength-training exercises

Appetite control Delayed appetite Inappropriate appetite

Psychological benefits Self-esteem

Choosing activitiesSpot reducing

Wt Loss Strategies – Environmental Influences

Factors surrounding eating experience and the food itself

Atmosphere Pleasant and comfortable equals more food

Accessibility Less effort needed to obtain food, more food eaten

SocializingDistractions

Wt Loss Strategies – Environmental Influences

Presence Sight, smell, or thought of food can prompt eating

Multiple choice Large assortments of foods increase consumption

Package and portion sizesServing containers

Weight Loss Strategies – Behavior & Attitude

Behavior modification Positive, matter-of-fact attitude

Become aware of behaviors Keep record

Change behaviors

Weight Loss Strategies – Behavior & Attitude

Cognitive skills Problem solving Cognitive restructuring

Personal attitude Understand personal relationship with food Sound emotional health

Support groups

Weight Loss Strategies – Weight Maintenance

Successful weight loss Plateau

Prevalence of successful weight loss Difficult to determine

Weight lossComponents of successful weight lossChanges in metabolismTakes more to prevent weight regain than to

prevent weight gain

Preventing Weight Gain

Preventing weight gain would benefit many people

Strategies are similar to losing weight Start earlier

Public Health Programs

Possibly change environment through public health law

Stretch beyond individual

Underweight

Affects no more than 5% of U.S. adultsWeight gain is a matter of healthWeight gain may be difficultDemand for energy contributes to

underweightDifficult to gain weightLearn new habits and like new foodsUnderweight vs. anorexia nervosa

Weight-Gain Strategies

Key diet planning strategiesEnergy-dense foods Exercise