Expresses the dietary energy supply as a percentage of the average dietary energy requirement in the country. The average supply of calories for food consumption of each country or region is normalized by the average dietary energy requirement estimated for its population in order to provide an index of adequacy of the food supply in terms of calories. Analyzed together with the prevalence of undernourishment, it allows the determination of whether undernourishment is mainly due to the insufficiency of the food supply or to poor distribution.