Nutrition, onset of disease, and longevity in the rat.

The effect of food restriction in rats to a level 46% below the intake of those fed ad libitum was studied in relation to onset of disease and longevity. Dietary restriction at this level kept adult rats in a nutritional state short of the development of excess body fat, and had little effect on skeletal growth or sexual maturity. Onset of microscopically observed renal, vascular, myocardial and skeletal muscle lesions, as well as mammary fibroadenoma in females, was delayed and resulted in greater longevity. Life expectancy of male rats was increased by 25% and of females by 39%. Time of onset of disease appears to be regulated by a common factor which is influenced by dietary intake.