Acute effects of exercise on food intake in obese and nonobese women.

The animal model of exercise-induced anorexia was employed in humans to develop a laboratory paradigm for studying the acute effect of exercise on food intake. Each of nine obese and nine nonobese women exercised either strenuously (90 W) or moderately (30 W) on a cycle ergometer for 40 min or rested in the laboratory on each of 3 nonconsecutive days. Intake of a liquefied test meal (1.04 kcal/g) eaten 15 min after exercise was significantly less after the strenuous (620 g) than after the moderate (754 g) exercise in the nonobese women but was no different after the two conditions (532 g after strenuous, 581 g after moderate) in the obese women. Heart rate and energy expenditure were increased in proportion to the exercise by the same amount in both groups. The results demonstrate for the first time that food intake is reduced immediately after strenuous exercise in nonobese women, as it is in animals, and validate the feasibility of this laboratory paradigm.