1. If you ordinarily expend 2000 kcal/day and you go on a diet of 1500 kcal/day, about how long will it take to diet off 1.0 lb of fat? A person who expends 1800 kcal/day goes on a diet of 1200 kcal/day without a change in activities. Estimate how much fat she will lose if she stays on this diet for three weeks. Exercise 18.1A EXAMPLE 18.1 Weight Loss Through Diet A person who expends 2200 kcal/day goes on a diet of 1800 kcal/day and adds exercise activities that use 180 kcal/day. Estimate how much fat he will lose if he stays on this program for three weeks. Exercise 18.1B Solution You will use 2000 – 1500 = 500 kcal/day more than you consume. There are about 3500 kcal in 1.0 lb of fat, and so it will take (Keep in mind, however, that your weight loss will not be all fat. You will probably lose more than 1 lb, but it will be mostly water with some protein and a little glycogen.) 3500 kcal x= 7 days 1 day 500 kcal

2. A 135-lb person doing high-impact aerobics burns off about 6.9 kcal/min. How long would the person have to exercise to burn off 1.0 lb of adipose (fat) tissue? Walking a mile burns off about 100 kcal. About how far do you have to walk to burn off 1.0 lb of fat? Exercise 18.2A EXAMPLE 18.2 Weight Loss Through Exercise A moderately active person can calculate the calories needed each day to maintain proper weight by multiplying the desired weight (in pounds) by 15 kcal/lb. How many calories per day do you need to maintain a weight of 150 lb? Exercise 18.2B Solution One pound of adipose tissue stores 3500 kcal of energy. To burn it off at 6.9 kcal/min requires It takes about 500 min (more than 8 hr) to burn off 1 lb of fat, even doing high-impact aerobics. (However, you don’t have to do it all in one day.) 3500 kcal x= 500 min 1 min 6.9 kcal

3. What is the BMI for a person who is 6 ft 1 in. tall and weighs 205 lb? What is the BMI for a person who is 5 ft tall and weights 120 lbs? Exercise 18.3A EXAMPLE 18.3 Body Mass Index What is the maximum weight, in pounds, that a person 5 feet 10 inches tall can maintain and have a BMI that does not exceed 25.0? Exercise 18.3B Solution The person’s height is (6 x 12) + 1 = 72 + 1 = 73 in. The body mass index is 27. BMI = = 27 705 x 205 73 x 73