'Again, it is clear in this regard that physical activity is one of the most important behavioural factors in enhancing weight loss maintenance and improving long-term weight loss outcomes,' Jakicic said.

Janet Rankin, fellow of the ACSM, an expert in nutrition and exercise, observed: 'A practical response to the claim that exercise makes you eat more and gain weight is to look around. If this were the case, wouldn't those who regularly exercise be the fattest? Obviously that isn't the case.'