Weight loss and exercise
-
Upload
aprilee-carey -
Category
Health & Medicine
-
view
219 -
download
5
description
Transcript of Weight loss and exercise
Weight loss and exercise
ObesityOverweight: 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 LossCaloric 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 OutCaloric 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 RateGenetics
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] 4
0%
fat
60%
fat
~2
0%
fat
30
0 t
ota
l kca
l s
600
tota
l kc
als
900
tota
l kc
als
Successful Weight Loss
diet and exercise
Diet: limited caloric intake (source of calories is unimportant)
Exercise: increase physical activity
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
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
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