The document discusses obesity, weight loss, exercise, and weight gain. It defines obesity metrics and provides US obesity statistics. Weight loss occurs through caloric imbalance where energy expenditure exceeds energy intake. Exercise alone is less effective for weight loss than diet alone but is important for maintaining lost weight. Weight gain results from sustained caloric surplus where intake exceeds expenditure. Genetics also influence body type and predisposition to gain or lose weight.

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
1. Resting Metabolic Rate = 60-75%
2. Thermic effect of food = 10%
3. 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. Exercise and
Fat
Metabolism
Is low-intensity
exercise best for
burning fat? [A
Closer Look 4.3]
40%fat
60%fat
~20%fat
300totalkcals
600totalkcals
900totalkcals

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

24. Genetics
Body Type / Somatotype
Weight Gain

25. 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.
Weight Gain

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. 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
Weight Gain