950

PART 4 Regulation and Maintenance

kilocalories lost in exercise reveals why losing weight can be diffi-cult. For example, if brisk walking uses 225 kcal/h, it takes 20 min-utes of brisk walking to burn off the 75 kcal in one slice of bread(75/225 = 0.33 h). Research suggests that a combination of appropri-ate physical activity and appropriate kilocaloric intake is the bestway to maintain a healthy body composition and weight.

ASSESS YOUR PROGRESS

47. What is metabolic rate? How is it measured?

48. What is BMR? What factors can alter BMR?

49. What is the thermic effect of food?

50. BMR, the thermic effect of food, and muscular activityeach account for what percentage of total energyexpenditure?

51. How are kilocaloric input and output adjusted to maintainbody weight?

Predict 5

If watching TV uses 95 kcal/h, how long does it take to burn off thekilocalories in one cola or beer (see table 25.1)? If jogging at a pace of6 mph uses 580 kcal/h, how long does it take to use the kilocaloriesin one cola or beer?