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

9. 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

11. 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

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

13. 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

14. 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

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

16. 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

17. 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

18. 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

19. 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

20. 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

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

23. 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.

24. 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

25. 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

26. 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

27. 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

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

29. 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