UK scientists have said that exercising after meals helps weight loss as it boosts the hormones which suppress our appetite. Experiments carried out suggest that active people feel less hungry after exercise, even when their meals were bigger as sporty people gained fewer calories overall because they burned off more.

The research by the Surrey University and Imperial College London saw 12 volunteers given the same breakfast. An hour later, half of them worked out for an hour on an exercise bike while the other half sat quietly. Both groups were then left for another hour and then allowed to eat as much as they liked.

Those who exercised after their breakfast unsurprisingly burned more calories than those who sat quietly, 492 kcal compared to 197 kcal. When given the chance to eat afterwards, the people who had exercised tended to eat more, 913 kcal versus to 762 kcal. However, when the amount of energy burned during exercise was taken into account, the active people took in fewer calories overall, 421 kcal compared to 565 kcal for the inactive group.

The scientists also saw the levels of hormones called PYY, GLP-1 and PP, which tell the brain when the stomach is full, increase during and immediately after exercise, and the volunteers said they felt less hungry during this time.

Researcher Dr Denise Robertson said: "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. 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."

Dr Ian Campbell, medical director of the charity Weight Concern, said: "This is an interesting study. Patients often report that they feel increased hunger and eat more after exercise. 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. 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."

Dr John McAvoy, a GP with a special interest in obesity, said the study was a "significant contribution to understanding the complex mechanisms of energy balance. It will be of much more interest to the pharmaceutical industry than the general public at this stage, for the simple reason that most people view exercising so soon after eating as akin to putting your fingers down your throat. For exercise to contribute to weight control it should be sustainable over the long term and enjoyment remains a critical factor to this end."

Following the study, experts have recommended that people do at least 30 minutes of physical activity on five or more days a week.