Scientists have discovered why the Atkins diet is so successful at helping people lose weight. Curbing carbohydrates reduces overall appetite so people on Atkins-type diets shed more pounds more quickly.

The small study, by a team from Temple University, Philadelphia, involved just 10 volunteers who were confined to hospital for three weeks so every calorie they consumed and expended could be measured. It revealed that carbohydrates eaten by the volunteers - potatoes, bread and cakes - actually stimulated their appetite so they ate more of other foods as well. Claims that eating less carbohydrate changed the metabolism to promote weight loss were denied by the researchers.

Over the three weeks of the study, the average daily calorie consumption fell by a third.