How much should we eat? The association between energy intake and mortality in a 36-year follow-up study of Japanese-American men.

Energy restriction extends life span and lowers mortality from age-related diseases in many species, but the effects in humans are unknown. We prospectively examined this relationship in a large epidemiological study of Japanese-American men. We followed 1915 healthy nonsmokers, aged 45-68 years at study onset, for 36 years. Twenty-four-hour recall of diet was recorded at baseline, and follow-up was for all-cause mortality. After adjustment for age and other confounders, there was a trend toward lower mortality in the second quintile of energy intake, suggesting that men who consumed 15% below the group mean were at the lowest risk for all-cause mortality. Increased mortality was seen with intakes below 50% of group mean. Thus, we observed trends between low energy intake and reduced risk for all-cause mortality in humans until energy intake fell to less than half the group mean, consistent with previous findings in other species.