Chapter 30


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Chapter 30

  1. 1. CHAPTER 30 OVERWEIGHT, OBESITY, AND WEIGHT CONTROL DEFINE KEY TERMS AND CONCEPTS 1 BMI 2 Overweight 3 Overfat 4 Obesity 5 Mutant gene 6 Leptin 7 Obesity drugs 8 Futile metabolism 9 Age changes in body fat 10 Specific risks of obesity 11 How fat is too fat? 12 Android-type obesity 13 Gynoid-type obesity 14 Waist-to-hip girth ratio and health risk 15 Adipocytes 16 Lipoprotein lipase 17 Clinically severe obesity 18 Fat cell hypertrophy 19 Fat cell hyperplasia 20 Energy balance equation 21 Yo-yo effect 22 National weight control registry 23 Set-point theory 24 Ketogenic diet 25 High-protein diet
  2. 2. 26 Very-low calorie diet 27 Hydration and body fat loss 28 Recovery afterglow 29 Diet plus exercise 30 Spot reduction 31 Gaining weight STUDY QUESTIONS Obesity What percentage of American men and women currently participate in weight loss programs? Males: Females: WORLDWIDE EPIDEMIC What BMI corresponds to the overweight condition? What percentage of the following members of the U.S. population are considered obese? Adults: Children: Adolescents: List 2 reasons to classify individuals as overweight and obese. 1. 2. Overweight, Overfat, and Obesity: No Unanimity for Terminology Distinguish between the terms overweight, overfat, and obese. Overweight: Overfat: Obesity: A PROGRESSIVE LONG-TERM PROCESS At what age do most adults develop excessive overfatness?
  3. 3. EXCESSIVE BODY FAT DOES NOT NECESSARILY RELATE TO OVEREATING List 5 factors that predispose a person to excessive weight (fat) gain. 1. 2. 3. 4. 5. GENETICS INFLUENCES BODY FAT ACCUMULATION Genetic factors explain approximately _________ percent of the variation in weight gain among individuals. Mutant Gene? Explain the role of the mutant “ob” gene in obesity development. Leptin Describe the role of leptin relative to eating behavior. Describe the relationship between plasma leptin and adipose tissue mass in normal and obese individuals. What is the effect of exercise on leptin levels? Explain the influence of the UCP2 gene. List 4 drugs that combat obesity and their mechanisms of action. Drugs Mechanisms of action 1. 2. 3.
  4. 4. 4. Leptin, Body Composition, and Anorexia Nervosa Do anorectics have high or low leptin levels? Influence of Racial Factors Why do black women experience greater difficulty achieving a goal body weight compared to white counterparts? A Word of Caution What variable needs careful evaluation when comparing ethnic differences in body composition? Physical Inactivity: A Crucial Component in Excessive Fat Development Discuss how increases in body fat with age can be more a function of physical inactivity than age itself. Age-Related Changes in Body Composition of Adult Men and Women At approximately what age does body fat increase in adult men and women? Men: Women: Benefits of Increased Energy Output With Aging Discuss the roll of regular exercise in middle age in blunting the tendency for weight gain. About how much more should an active male expect to weigh at age 50 compared to age 20? HEALTH RISKS OF EXCESSIVE BODY FAT List 6 comorbidities of obesity. 1. 2. 3. 4. 5. 6.
  5. 5. An Economic Burden for Mature Women About how much less is the net worth ($) of an obese woman compared to a nonobese peer? Discuss weather unfit, lean men show a higher or lower risk of all-cause mortality than overfat, fit men. Excessive Fatness in Childhood and Adolescence Predicts Adverse Health Effects in Adulthood Increased weight gain during adolescence increases what four risk factors in adulthood? 1. 2. 3. 4. Excessive Fatness in Childhood and Adolescence Predicts Adverse Health Effects Discuss the health risks of being overweight as an adolescent, regardless of final body weight as an adult. Specific Risks List 10 specific health risks of excessive body fat. 1. 6. 2. 7. 3. 8. 4. 9. 5. 10. CRITERIA FOR OBESITY: HOW FAT IS TOO FAT? Percent Body Fat What level of percentage body fat indicates borderline obesity in adult men and women? Men: Women: Criterion for Children Describe an objective measure to assess excess body fat in children. Regional Fat Distribution Describe the 2 general types of body fat distribution. 1.
  6. 6. 2. Give the anatomic location of the waist and hip girth used in computing the waist-to-hip girth ratio? Waist: Hip: List the waist-to-hip girth ratio associated with significant health risk in men and women. Men: Women: Lipoprotein Lipase Affects Body Fat Distribution Explain the role of lipoprotein lipase in body fat distribution. Varieties of Human Obesities Give a criterion for identifying severe clinical obesity? Adipocyte Size and Number: Hypertrophy Versus Hyperplasia List the 2 ways fat cells increase in the body. 1. 2. Write the formula for calculating total adipocyte number. Cellularity Differences Between Nonobese and Obese Persons Give average values for fat cell size and fat cell number in obese and nonobese adults. Obese Nonobese Cell size Cell number Effects of Weight Loss When a person reduces body mass, describe the changes in fat cell size and fat cell number. Fat cell size: Fat cell number: Effects of Weight Gain When a person increases body mass, what generally occurs to fat cell size and fat cell number? Fat cell size:
  7. 7. Fat cell number: Possibility That New Adipocytes Form How does massive weight gain in adulthood impact adipocyte development? Adipocyte Development Animal Studies Do rat adipocytes increase in size or number after 15 weeks of age? Human Studies Cell Size Describe the general pattern for adipocyte size in humans from birth to adulthood. Cell Number Indicate 3 general stages in adipocyte number development in humans. 1. 2. 3. Can Body Fat be Modified Early in Life? How much maternal weight gain during pregnancy generally increases offspring fatness? Principles of Weight Control: Diet and Exercise ENERGY BALANCE: INPUT VERSUS OUTPUT Write the energy balance equation. List 2 ways to unbalance the energy balance equation in the direction of weight loss. 1. 2. DIETING FOR WEIGHT CONTROL What is generally considered a prudent daily caloric deficit (by food restriction) to induce weight loss?
  8. 8. Long-Term Success Summarize the general trend for long-term success in weight loss. National Weight Control Registry List 3 major findings from the NWCR program for successful weight loss. 1. 2. 3. Weight Loss Improves Disease Risk Biomarkers List 3 disease risk factors that become favorably modified when an obese person loses weight. 1. 2. 3. Set-point Theory: A Case Against Dieting Summarize the main premise of the set-point theory in body fat accumulation. Resting Metabolism Decreases Discuss the effect of weight loss through dieting on RMR. Biologic Feedback Mechanism What is the effect of weight loss in obese people on lipoprotein lipase? Weight Cycling: Going No place Fast? List 2 possible negative aspects of weight cycling. 1. 2.
  9. 9. Dieting Extremes Low Carbohydrate- Ketogenic Diets Describe the rationale for a ketogenic diet for weight loss. High-Protein Diets Describe the rationale for a high-protein diet for weight loss. Semistarvation Diets List 4 negative aspects of a VLCD. 1. 2. 3. 4. FACTORS THAT AFFECT WEIGHT LOSS Early Weight Loss is Largely Water Water makes up about _____ percent of the weight lost during the first week of an energy deficit. Protein’s contribution to weight loss increases from ___% initially to about ____% after the fourth week. Hydration Level Describe the effect of water intake on weight loss and fat loss during a reduced caloric intake Weight loss: Fat loss: Longer-Term Deficit Promotes Fat Loss Why is it crucial for body fat loss to maintain a caloric deficit for an extended duration? EXERCISE FOR WEIGHT CONTROL Not Simply Gluttony Cite specific evidence that obesity is not necessarily related to excessive food intake.
  10. 10. Increasing Energy Output Describe the effects of regular exercise on central adipose tissue accumulation. Misconceptions About Exercise Misconception 1. Exercise and Food Intake Discuss whether all levels of increased physical activity stimulate a compensatory increase in food intake. Misconception 2. Caloric Stress of Physical Activity Explain if the calorie-expending effects of exercise are cumulative? The Recovery “Afterglow” Give approximate values (and their significance for weight loss) for the recovery “afterglow” following submaximal exercise of less than 80 minutes duration. Value: Significance: EFFECTIVENESS OF REGULAR EXERCISE How many days does it take to lose 13.6 kg of body fat assuming a daily caloric deficit of 300 kcal? Dose-response Relationship Describe the concept of dose-response for the effectiveness of physical activity for weight loss. Walking-Running for Different Durations True or False: The longer you exercise the more weight you lose. Explain. Exercise Frequency Describe the optimal exercise frequency for weight loss. Start Slowly and Progress Gradually Meaningful changes in body weight and body composition require at least ____ weeks. Self-selected Energy Expenditures: Mode of Exercise Which exercise mode generally provides the most suitable exercise to maximize energy expenditure during self-selected intensities of continuous exercise?
  11. 11. DIET PLUS EXERCISE: THE IDEAL COMBINATION Explain the main reason why exercise plus diet remains the ideal combination for weight loss? A Reality Check List 3 long-term lifestyle changes needed for successful weight control. 1. 2. 3. SPOT REDUCTION DOES NOT WORK Where on the body does fat reduction occur? Why doesn’t specific exercise promote fat loss at specific body sites (i.e., side leg raises reduces inner thigh fat). Areas of Fat Loss What body region tends to be the most resistant to weight loss? Possible Gender Differences Explain why men may be more responsive than women to the influence of exercise on weight loss. GAINING WEIGHT: THE COMPETITIVE ATHLETE’S DILEMMA Justify your opinion as to the “best” way for an athlete to gain body mass. Unsupported Hype Can excess protein intake promote increased muscle development? Increase the Lean, Not the Fat Describe the best approach to use exercise to promote increases in muscle mass. Give a safe recommendation for protein intake for individuals desiring to gain muscle mass.
  12. 12. How Much Gain to Expect How much lean body mass can a male and female expect to gain with a structured program of resistance training? Male: Female: