Role and benefits of carbohydrate in the diet: key issues for future dietary guidelines

There is now widespread advocacy for a reduction in fat intake. Furthermore, there is little evidence that an increase in protein intake would be advisable. Therefore, a greater proportion of carbohydrate energy in the diet has become a central tenet of current dietary advice. A careful examination of the benefits of a "high"-carbohydrate diet must therefore occupy our attention. Three aspects of the role of carbohydrate in the diet will be considered: 1) the role of carbohydrate in the control of food intake in humans, 2) the effect of carbohydrate on energy metabolism as measured by long-term feeding experiments in small numbers of human subjects, and 3) whether a large carbohydrate intake leads to increased lipogenesis in humans.