Caloric Restriction Nutrition

The first work that linked caloric restriction to an extension of life span was published in 1935 by Clive McCay and his colleagues, nutritionists at Cornell University in Ithaca, New York. Their studies showed that restricting the food intake of rats soon after weaning increases their length of life. Since then, this finding has been confirmed many times in rats, mice, and hamsters. In most of these studies, animals fed ad libitum (allowed to eat as much as they want) were compared to those restricted to 50 to 60 percent of that amount of food, with care being taken to provide a sufficient diet to avoid malnutrition.

Decreasing food intake has also been found to extend the length of life of nonmammalian species such as fish, flies, nematodes, and water fleas. It has yet to be established that restricting food intake has such an effect on all, or most, species, however. This is because the effect of reducing food intake on longevity has yet to be assessed in most species, and also because the nutritional requirements of most species are not sufficiently known to be certain that one is not dealing with the effects of malnutrition.