Weight loss and exercise

1. Weight loss and exercise

2. Obesity • Overweight: BMI = 25.0 - 29.99 • Obesity • BMI ≥ 30 • Body fat > 25% for men • Body fat > 30% for women • Americans: • Overweight: 32% • Obese: 34%

4. Obesity • Genetic factors • 25% of the transmissible variance for fat mass and percent body fat • Cultural factors (30%) • Individual choices (45%)

5. Calorie • A measure of HEAT • (1 calorie = heat required to raise 1 gram of water by 1 degree Celcius in temperature) • Heat, or Calorie, represents Energy

6. Weight Loss • Caloric balance or imbalance • Energy In > Energy Out = Weight Gain • Energy In < Energy Out = Weight Loss • Examples • Energy In: Big Mac 540 kcal • Energy Out: Run 40 minutes

7. Energy Out • Caloric expenditure • Resting Metabolic Rate = 60-75% • Thermic effect of food = 10% • Physical activity = 15-30% of daily caloric expenditure • Example 3000 calories in one day • RMR = 1,800-2250 kcal • TEF = 300 kcal • PA = 450-900 kcal

8. Energy In • Fat = 9 calories per gram • Alcohol = 7 calories per gram • Carbohydrate = 4 calories per gram • Protein = 4 calories per gram

9. Weight Loss • Reduce ‘Energy In’ and/or Increase ‘Energy Out’... • …500-1000 fewer calories per day • (3,500-7,000 fewer calories per week) • Recommendations: • 1-2 lbs of weight loss per week

10. Reducing Caloric Intake

11. Reducing Calorie Intake

12. Rapid Weight Loss / Low Calorie Diets • = weight loss greater than 1-2 pounds per week. • Where does the weight loss come from? • Water loss, Muscle loss, etc. • Metabolic rate?

13. Caloric Intake and Resting Metabolic Rate

14. Metabolic Rate • Resting Metabolic Rate is VO2 measured at rest • ave. resting VO2 = 3.5 ml/kg/min • Estimated RMR = 1 kcal/kg/hour • For a 183 pound person, RMR = 2000 kcals. • 60-75% of daily caloric expenditure

15. Metabolic Rate • Genetics • Gender • Fat-free mass • Dieting • Hormones (e.g. Thyroid hormones, etc) • Over eating (thermogenesis) • Medications/Drugs

16. Increasing Caloric Expenditure

17. Physical Activity and Body Fat

18. Exercise and Weight Loss • Exercise alone • less effective than diet alone • Duration: • > 2000 calories/wk • EXAMPLES OF KCAL expenditure • 0.77 kcal / kg / mile for walking • 1.53 kcal / kg/ mile for running

19. Exercise and Weight Loss • Exercise may be most critical to help maintain weight loss • Exercise helps to maintain muscle mass and metabolic rate

20. Exercise and Weight Loss • Aerobic exercise v Resistance exercise • WORKOUT CALORIES • resting metabolic rate • Aerobic Exercise: Duration versus Intensity

21. Fat Burning Zone?

22. 900 total kcals 600 total kcals 300 total kcals 40% fat ~20% fat 60% fat Exercise and Fat Metabolism • Is low-intensity exercise best for burning fat? [A Closer Look 4.3]

23. Successful Weight Loss • diet and exercise • Diet: limited caloric intake (source of calories is unimportant) • Exercise: increase physical activity

24. Weight Gain • Genetics • Body Type / Somatotype

25. Weight Gain • Caloric intake greater than caloric expenditure. • 25-30 calories per pound of body weight to gain weight(20 calories per pound to maintain weight) • ...or... • 500-1000 extra calories per day.

26. Weight Gain • Caloric distribution • Carbohydrates - 60 to 70% of total calories • Protein - 10 to 15% of total calories • Fat - remainder of total calories.

27. Weight Gain • Example for 200 pounds. • Carbohydrates: energy for anabolism (~3000 kcals) • Protein: amino acids for anabolism (~1200 kcals) • Fat: can’t avoid it (~800 kcals) • PSM

28. Weight Gain • Recovery/Rest • Eccentric muscle contractions damage muscle proteins. • Proteins are replaced for the next 48 hours or more. • Adequate rest and recovery period are critical for complete muscle repair and growth