Obesity, Exercise and Weight Control

HFIT 325 Exercise PhysiologyAmerican University

Reference book: Power’s 5th Edition

Obesity

OBESITY IS A MEDICAL TERM MEANING THE STORAGE OF EXCESS FAT IN THE BODYNORMAL RANGE OF FAT %

MALE 3% - 20%, OVERFATNESS >20%FEMALE 12% - 30%, OVERFATNESS >30%

Use BMI of ≥ 30 as obesity, 15% in 1976-1980 to 23.3% in 1988-1994 to 30.9% in 1999-2000

Review:1. Fat %2. Location of fat3. 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. 16.3 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 Ff

2. Calculate the fat-free weight: FFW = BW - FW

3. Calculate the desirable target weight:

TW = ----------------FFW

(1 – Fx)

TW = ---------------------- BW (1 – Ff)

(1 – Fx)

FW = fat weightBW = measured body weightFf = fractional expression of the percent body fatFFW = fat-free weight or lean body weightTW = desired target weightFx = 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 lbStep 2. FFW = BW – FW = 200 – 54 = 146 lbStep 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 & growthQuantity of food for body maintenance & growth

Too much foodToo much foodPositive energy balancePositive energy balance

Energy needs exceed that produced from foodEnergy needs exceed that produced from foodNegative energy balanceNegative energy balance

Gain weightGain weight

Body consumes itsBody consumes its own fat, then protein, own fat, then protein, Loss weightLoss weight

Energy Balance & Weight ControlEnergy Balance & Weight Control

Energy Balance & Weight ControlEnergy Balance & Weight Control

Daily caloric need = BEE + GA + ExDaily caloric need = BEE + GA + Ex

BEE = basal Energy ExpenditureBEE = basal Energy ExpenditureGA = Energy Cost of General Activities (eating, walking, sitting, reading..GA = Energy Cost of General Activities (eating, walking, sitting, reading..EX = Energy Cost of Exercise EX = Energy Cost of Exercise

Ross & Jackson: equations for estimating basal energy expenditure,Ross & Jackson: equations for estimating basal energy expenditure,In calories, that takes into account age, gender, height, and weight.In calories, that takes into account age, gender, height, and weight.

Basal Energy Expenditure (BEE)Basal Energy Expenditure (BEE)

For males: BEE = 66 + (13.7 X Wt) + (5 X Ht) – (6.9 X A)For males: BEE = 66 + (13.7 X Wt) + (5 X Ht) – (6.9 X A)

For female: BEE = 665 + (9.6 X Wt) + (1.7 X Ht) – (4.7 X A)For female: BEE = 665 + (9.6 X Wt) + (1.7 X Ht) – (4.7 X A)

Wt: kg, Ht: cm, A: yearsWt: kg, Ht: cm, A: years

Energy Cost of General Activities (GAEnergy Cost of General Activities (GA)) GA = BEE X 20%GA = BEE X 20%

Energy Cost of Exercise (EX)Energy Cost of Exercise (EX)

Energy Cost of Exercise (EX)Energy Cost of Exercise (EX)

Fox’s p 450, Table 16.5Fox’s p 450, Table 16.5

Application:Application:

Current weight: 200 lb (90.7 kg)Current weight: 200 lb (90.7 kg)Fat % = 27%Fat % = 27%Height: 70 in (178 cm)Height: 70 in (178 cm)

Kcal/day= BEE + GAKcal/day= BEE + GA

BEE = 66 + (13.7 X 90.7 kg) + (5 X 178 cm) – (6.9 X 27)BEE = 66 + (13.7 X 90.7 kg) + (5 X 178 cm) – (6.9 X 27) = 66 + 1243 + 890 – 186 = 2013 kcal= 66 + 1243 + 890 – 186 = 2013 kcalGA = BEE X 20% = 2013 X 20% = 403 kcalGA = BEE X 20% = 2013 X 20% = 403 kcalBEE + GA = 2416 kcalBEE + GA = 2416 kcal

This is what the subject must consume daily to maintain his currentThis is what the subject must consume daily to maintain his currentweight at 200 lbweight at 200 lb

How to loss 22 lb ????How to loss 22 lb ????

3500 kcal/lb X 22lb = 77,000 kcal 3500 kcal/lb X 22lb = 77,000 kcal

How long will it take him to achieve this goal?How long will it take him to achieve this goal?

INPUTINPUTReduce total caloric intakeReduce total caloric intake500 kcal500 kcal500 kcal X 7 days = 3,500 kcal500 kcal X 7 days = 3,500 kcal

OUTPUTOUTPUTPhysical activity Physical activity For example: joggingFor example: jogging8.5 min/mile, 30 min/day, 5/wks8.5 min/mile, 30 min/day, 5/wks

EX = (0.09 kcal/lb/min) X 200 lb X 30 min = 540 kcal/runEX = (0.09 kcal/lb/min) X 200 lb X 30 min = 540 kcal/run 540 kcal X 5 session/wk = 2,700 kcal/w540 kcal X 5 session/wk = 2,700 kcal/w

3,500 + 2,700 = 6,200 kcal/w3,500 + 2,700 = 6,200 kcal/w

6,200 kcal / 3,500 kcal = 1.75 lb6,200 kcal / 3,500 kcal = 1.75 lb

22 lb22 lbOrOr34 lb34 lbHow many weeks?How many weeks?

22/1.75 = 12-13 weeks, 34/1.75 = 19-20 weeks