(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 leptin’s 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 don’t
seem to work as well.”
SOURCE: The Endocrine Society’s 90th Annual Meeting in San Francisco, June 2-15,
2008
