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Chapter 6: Overweight and Obesity

Chapter 6: Overweight and Obesity. Introduction and Epidemiology. Obesity is a chronic disease Similar pathophysiology as other chronic diseases Develops over a relatively long period of time and persists Disease process may resolve with appropriate treatment.

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Chapter 6: Overweight and Obesity

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  1. Chapter 6: Overweight and Obesity

  2. Introduction and Epidemiology Obesity is a chronic disease • Similar pathophysiology as other chronic diseases • Develops over a relatively long period of time and persists Disease process may resolve with appropriate treatment. • Lifestyle change is the preferable treatment • Lifestyle, drugs, and surgery may be complimentary in severe cases (BMI >35.0) • Drug therapy for weight loss is unsatisfactory over the long term

  3. Obesity Epidemic • 1995: 10-14% of population overweight/obese • 2005: 17 states report >25% obese • 2004: >66% overweight/obese • Obese and overweight children approx 30% • 2004: >75% of African-American women and Mexican-American adults overweight/obese

  4. Obesity Epidemic (con’t) Reasons for international obesity complex: • Often exists among undernourished populations • Excess consumption of high caloric density foods • Lack of physical activity Obesity, type 2 diabetes, MetS epidemic: • Currently 24 million with type 2 diabetes • 57 million with “pre-diabetes” • 25% of adults have or at risk for type 2 diabetes

  5. Pathophysiology of Obesity Adipokines • Produced, secreted by adipocytes • Affect inflammation, metabolism, immune function, vascular function, and insulin secretion • Influence insulin secretion/IR, hunger, appetite, pathophysiology, metabolism and biochemistry of adipose tissue

  6. Pathophysiology of Obesity (con’t) • Inflammatory effects of food in the Western Dietary pattern • Sedentary lifestyle promotes pathophysiology associated with chronic disease and obesity

  7. Pathophysiology of Obesity (con’t) Total mass of fat cells and fat tissue: • influences pathophysiology • causes widespread metabolic and physiological dysfunction • excess adipose tissue fueled by sedentary lifestyle and poor nutrition is self-promoting

  8. Defining Obesity and Associated Health Risk Different standards to assess and define • Accumulation of excess adipose tissue • Percent body fat, waist circumference, BMI, WHR predict risk • WHR may be best indicator of pathology

  9. Weight Loss and Weight Loss Maintenance Diets and Weight Loss • Common characteristics include: • Adequate caloric intake to sustain PA and exercise • Variety of foods • Food pattern that can be maintained • Based on individual preferences, physiology, sound behavioral change principles

  10. Low-Calorie Diets • Negative caloric balance required • Caloric restriction: • 1000-1200 calories/day (women) • 1200-1400 calories/day (men) • Don’t limit/emphasize a particular food group • NCEP Step 1 diet • DASH Diet • Weight Watcher’s • High fiber/low GI

  11. Low-Carbohydrate Diets • Demonstrated effective for weight loss • Not demonstrated effective over the long term • Demonstrated effective in modifying risk factors • Some high protein and/or high fat • Choosing high fiber/low refined carbohydrates is healthier

  12. Low-Fat Diets • Restrict fat calories to 15-20% of total • Ornish, Pritikin Diets • Effects on weight loss are significant • Decrease cholesterol, LDLs, HDLs • Increase triglycerides • Adherence and compliance may be problematic

  13. Negative Caloric (Energy) Balance • Prescribe exercise and caloric restriction • Negative energy balance required for weight loss • Equivalent energy balance required for weight maintenance

  14. Diet Composition • Diet composition and caloric restriction are related to weight loss and weight maintenance • Restricting calories helps establish negative caloric balance • Composition of calories consumed (dietary pattern) is important

  15. Exercise and Weight Loss • Increased PA required • Maintaining high PA after weight loss helpful • Sufficient PA sometimes difficult for extremely obese • Non—weight-bearing activities or water exercise may be helpful • Increased caloric expenditure contributes significantly • 2000 calories/week from exercise required

  16. Exercise and Weight Loss (con’t) • May take >caloric expenditure to maintain weight after weight loss • Partially explained by the loss of muscle mass • PA (LTPA) added variable to increase negative energy balance • ≥ 10,000 steps/day

  17. Initial Exercise Prescription • Overweight or obese sustain exercise-related injuries more often • Higher intensity and frequency of exercise causes more injury • Progress intensity and duration slowly • Use short-duration, intermittent exercise >1 time per day • Assure success early for overweight, deconditioned

  18. The Optimal Lifestyle Program for Overweight and Obesity • Exercise, nutritional intervention change pathophysiology • Metabolic changes associated fat cell mass moderated • Achieving optimal weight, BMI, or WHR may normalize inflammation • Optimal program requires changes in dietary pattern, regular exercise, increased LTPA

  19. Figure 6.6. Successful weight loss programs combine dietary pattern changes (including caloric restriction), exercise and physical activity, and behavioral change.

  20. Digging Deeper: Exercise and Appetite • Exercise alone unlikely to stimulate increased appetite if program includes diet and exercise • Controversial but not an appropriate reason to remove exercise • Exercise not sole factor used to produce negative energy balance.

  21. Digging Deeper: Exercise and Appetite (con’t) King • 2 processes drive appetite regulation in response to exercise • Satiety is increased after training • Exercisers were progressively more satisfied after a meal as exercise progressed • Fasting, total daily hunger increased among non-responders

  22. Digging Deeper: Exercise and Appetite (con’t) • Majority of this research shows exercise does not increase appetite or EI • High-intensity exercise may produce a temporary decrease in appetite • Exercise unlikely to cause significant long-term effects on EI • Coupling between EI and EE may be a more important factor

  23. Digging Deeper: Exercise and Appetite (con’t) Mayer • Demonstrated uncoupling of EI, EE • Workers in sedentary jobs were heaviest, had highest EIs • EI “increases with activity only within a certain zone” (caloric expenditure) • The most sedentary workers had highest EI and lowest EE

  24. Digging Deeper: Exercise and Appetite (con’t) • Grehlin and Leptin: signal brain about nutritional status • Grehlin: • Signal from gut; information about food consumed • Leptin: • Signal from adipocytes about energy status

  25. Digging Deeper: Exercise and Appetite (con’t) • Both immediate feedback (Ghrelin), chronic feedback (Leptin) • Two forms of Grehlin (acylated and deacylated Grehlin)

  26. Digging Deeper: Exercise and Appetite (con’t) • Men, women respond differently • Men adjust EI and EE concurrently • no increased hunger response if EI = EE • Women have opposite effects • Hunger is stimulated after exercise and EI increased

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