Obesity, Exercise and Weight Control HFIT 325 Exercise Physiology American University Reference book: Power’s 5 th Edition

Obesity OBESITY IS A MEDICAL TERM MEANING THE STORAGE OF EXCESS FAT IN THE BODY NORMAL RANGE OF FAT % MALE 3% - 20%, OVERFATNESS >20% FEMALE 12% - 30%, OVERFATNESS >30% Use BMI of ≥ 30 as obesity, 15% in to 23.3% in to 30.9% in Review: 1.Fat % 2.Location of fat 3.Fat cell number and fat cell size

What is a desirable body weight? It is important to think in terms of a weight range rather than a single value T p446 Fox A reasonable goal would be to achieve ‘optimal fitness’ Example: for man, percent body fat is between 12-18% What would the corresponding body weight range be?

1.Calculate the fat weight: FW = BW X F f 2. Calculate the fat-free weight: FFW = BW - FW 3. Calculate the desirable target weight: TW = FFW (1 – F x ) TW = BW (1 – F f ) (1 – Fx) FW = fat weight BW = measured body weight F f = fractional expression of the percent body fat FFW = fat-free weight or lean body weight TW = desired target weight F x = fractional expression of the target percent body fat

Mr. Fittmann: Current weight: 200 lb (90.7 kg), Percent fat: 17%, Height: 70 in (178 cm), Age: 27 Goal: to achieve ‘optimal fitness” for body composition (12-18% body fat) What weight range would we recommend? Step 1. FW = BW X Ff = 200 X 0.27 = 54 lb Step 2. FFW = BW – FW = 200 – 54 = 146 lb Step 3. Target weight at 12% fat: TW = FFW / (1 – Fx) = 146 / (1-0.12) =146 / 0.88 = 166 lb Target weight at 18% fat: TW = FFW / (1 – Fx) = 146 / (1-0.18) =146 / 0.82 = 178 lb Fittmann must lose between 22 – 34lb of his 54 lb of body fat to achieve the Recommended 12% to 18% body fat. Also, it is not necessary that he lose 34 lb of body fat. That is merely the lower end of the recommended range.

Quantity of food for body maintenance & growth Too much food Positive energy balance Energy needs exceed that produced from food Negative energy balance Gain weight Body consumes its own fat, then protein, own fat, then protein, Loss weight Energy Balance & Weight Control

Daily caloric need = BEE + GA + Ex BEE = basal Energy Expenditure GA = Energy Cost of General Activities (eating, walking, sitting, reading.. EX = Energy Cost of Exercise Ross & Jackson: equations for estimating basal energy expenditure, In calories, that takes into account age, gender, height, and weight.

Basal Energy Expenditure (BEE) For males: BEE = 66 + (13.7 X Wt) + (5 X Ht) – (6.9 X A) For female: BEE = (9.6 X Wt) + (1.7 X Ht) – (4.7 X A) Wt: kg, Ht: cm, A: years Energy Cost of General Activities (GA) GA = BEE X 20% GA = BEE X 20% Energy Cost of Exercise (EX)

Fox’s p 450, Table 16.5

Application: Current weight: 200 lb (90.7 kg) Fat % = 27% Height: 70 in (178 cm) Kcal/day= BEE + GA BEE = 66 + (13.7 X 90.7 kg) + (5 X 178 cm) – (6.9 X 27) = – 186 = 2013 kcal = – 186 = 2013 kcal GA = BEE X 20% = 2013 X 20% = 403 kcal BEE + GA = 2416 kcal This is what the subject must consume daily to maintain his current weight at 200 lb How to loss 22 lb ????

3500 kcal/lb X 22lb = 77,000 kcal How long will it take him to achieve this goal? INPUT Reduce total caloric intake 500 kcal 500 kcal X 7 days = 3,500 kcal OUTPUT Physical activity For example: jogging 8.5 min/mile, 30 min/day, 5/wks EX = (0.09 kcal/lb/min) X 200 lb X 30 min = 540 kcal/run 540 kcal X 5 session/wk = 2,700 kcal/w 540 kcal X 5 session/wk = 2,700 kcal/w 3, ,700 = 6,200 kcal/w 6,200 kcal / 3,500 kcal = 1.75 lb 22 lb Or 34 lb How many weeks? 22/1.75 = weeks, 34/1.75 = weeks