Blame your failed diet on a natural reaction

Finding it difficult to lose weight? You need never feel guilty again, because British scientists have discovered a biological reason why diets so often fail, writes Tom Wilkie.

The answer to weight-loss lies in the head rather than the stomach, according to research published in today's issue of the journal Nature. Dr Philip Cowen and his colleagues at Oxford University's department of psychiatry have discovered that dieting alters the activity of a chemical in the brain, with the result that "dieting subjects are likely to experience urges to over-eat which will compromise efforts at continued food restriction".

Dr Elizabeth Clifford, a member of the team, said yesterday that their discovery may open the way to developing effective aids to slimming, by directly manipulating serotonin, the chemical messenger in the brain.

She also believes that the team's work will be important in understanding and treating the eating disorder bulimia nervosa, which is characterised by bouts of dieting followed by uncontrolled overeating.