Exercise Reduces Hunger for Some Women
Reported June 24, 2008
(Ivanhoe Newswire) Can exercise keep you from being hungry?
A new report finds exercise reduces hunger in lean women, but not in obese women, which may lead to them eating more after a workout.
Researchers from the University of Michigan wanted to better understand how changes in body fat level affect both appetite and a hormone called leptin. In animals, leptin curbs appetite when body fat increases. When the levels of leptin rise, the hormone seems to shut off appetite and motivate physical activity. However, as obese people become fatter and their leptin levels rise, they become resistant to how the hormone works.
The study looked at 20 postmenopausal women 10 were lean and 10 were obese. The women ate three weight-maintenance meals a day and did three experiments on three separate days. In two experiments they exercised on a treadmill in the morning and the afternoon. The intensity of the exercise was different, but in both experiments the women burned a total of 1,000 calories a day. In the third experiment, they did not exercise.
Obese women in the study said they were less hungry than lean women before meals and did not have any appetite suppression while they exercised.
Results show obese women had much higher leptin levels than lean women. During intense exercise, obese women did not have a drop in the production of leptin, as lean women did; only moderate-intensity exercise lowered their leptin.
Obesity interferes with leptins detection of exercise energy expenditure and with appetite suppression, lead author Katarina Borer, Ph.D., University of Michigan, was quoted as saying. Obese women perhaps need to consciously watch their calories because some of the hormonal satiety [fullness] signals dont seem to work as well.
SOURCE: The Endocrine Societys 90th Annual Meeting in San Francisco, June 2-15, 2008
