While most people prefer working out in the morning, before they have eaten anything, a new study now suggests that exercising after meals is better at promoting weight loss as it boosts hormones that suppress appetite.
Researchers at the Surrey University and Imperial College London conducted the study on 12 volunteers who were given the same breakfast.
One hour after the meal, half of the volunteers were asked to work out for a bike, and half were asked to just sit around.
An hour after that they were asked to consume as much food as they wanted.
The researchers reported that though unsurprisingly they had found that people who exercised not only burnt more calories and ate more than the people who sat quietly, what was surprising was that when the amount of energy burned during exercise was taken into account, the ones who exercised took in fewer calories overall - 421 kcal compared to 565 kcal for the inactive group.
The researchers also found that in people who had exercised, the levels of hormones called PYY, GLP-1 and PP, which tell the brain when the stomach is full, increased.
Volunteers also said they felt less hungry during this time.
Researcher Dr Denise Robertson said that the study showed that exercise after meals may be more helpful to people trying to lose weight.
"In the past we have been concerned that, although exercise burns energy, people subsequently ate more after working out. This would cancel out any possible weight reduction effects of exercise," the BBC quoted researcher her, as saying.
"But our research shows that exercise may alter people's appetite to help them lose weight and prevent further weight gain as part of a healthy, balanced lifestyle," she said.
"What this study shows is that, although total calorific intake is greater, the net result, because of the exercise taken, is a reduction in the net energy balance," added Dr Ian Campbell, medical director of the charity Weight Concern.
"Dieting is never easy. Increased physical activity is an essential part of any weight management programme, not just to expend more calories but also, as we see here, to help control our appetite too," he said.
The study is published in the Journal of Endocrinology.