How does exercise affect women's diets?

Dieters are often concerned that working out could make them hungry, but according to a recent small study, working out is more effective at limiting calorie consumption than food restriction and actually reduces appetite in the short-term.

Researchers at Loughborough University in England conducted a study of 12 fit women, analyzing the hormonal, psychological and behavioral reactions to calorie control through both exercise and food restriction over a nine hour period.

The two-part study first had the women achieve a calorie deficit through a moderate intensity 90-minute run on a treadmill. Then researchers had the women achieve the same calorie deficit through food restrictions.

Participants showed increased levels of the hunger hormone ghrelin and lower levels of a hunger suppressing hormone called peptide YY, when the energy deficit was achieved by limiting food intake.

The study also found that women ate an average of 944 calories at a buffet meal after food restrictions, compared to 660 calories when the same calorie deficits were created by exercise.

"Our findings provide a valuable contribution to the diet and exercise debate," said study author Dr. David Stensel, in a news release. "We've shown that exercise does not make you hungrier or encourage you to eat more - at least not in the hours immediately following it." A different study found that appetite perception, hormones, and food intake after exercise did not appear to be different between the sexes.

"Whether it's vigorous, moderate or light, any exercise facilitates a disconnection from food," explains Melodi Peters, a dietitian at Advocate Good Shepherd Hospital in Barrington, Ill. "This break from intake allows the brain to process that the person is actually full, which may facilitate eating less at a designated meal time."

"The take-home message is that exercise will not necessarily make you overeat or compensate by eating more food," the author said.