Transcript Weight loss and exercise

Weight loss and
exercise
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%
Obesity
Genetic factors
25% of the transmissible variance for fat mass and
percent body fat
Cultural factors (30%)
Individual choices (45%)
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
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
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
Energy In
Fat = 9 calories per gram
Alcohol = 7 calories per gram
Carbohydrate = 4 calories per gram
Protein = 4 calories per gram
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
Reducing Caloric Intake
Reducing Calorie Intake
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?
Caloric Intake and Resting
Metabolic Rate
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
Metabolic Rate
Genetics
Gender
Fat-free mass
Dieting
Hormones (e.g. Thyroid hormones, etc)
Over eating (thermogenesis)
Medications/Drugs
Increasing Caloric
Expenditure
Physical Activity and
Body Fat
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
Exercise and Weight
Loss
Exercise may be most critical to help maintain
weight loss
Exercise helps to maintain muscle mass and
metabolic rate
Exercise and Weight
Loss
Aerobic exercise v Resistance exercise
WORKOUT CALORIES
resting metabolic rate
Aerobic Exercise: Duration versus Intensity
Fat Burning Zone?
Exercise and Fat
Metabolism
Is low-intensity
exercise best for
burning fat? [A
Closer Look 4.3]
Successful Weight Loss
diet and exercise
Diet: limited caloric intake (source of
calories is unimportant)
Exercise: increase physical activity
Weight Gain
Genetics
Body Type / Somatotype
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.
Weight Gain
Caloric distribution
Carbohydrates - 60 to 70% of total calories
Protein - 10 to 15% of total calories
Fat - remainder of total calories.
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
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