Decades of work in mice and monkeys has shown that losing calories lengthens lives: animals eating up to 50% less live up to 50% longer. Certain biological changes accompany the dieting. Calorie-restricted animals have lower body temperatures and blood insulin levels than their freely fed counterparts, while maintaining higher levels of the hormone dihydroepiandrosterone.
Now some evidence suggests that, in people, these three biomarkers are also linked to a longer life. Drawing on data from 700 healthy men in the long-running Baltimore Longitudinal Study of Aging, researchers from the National Institute on Aging (NIA) report that men and monkeys with lower body temperatures, lower blood insulin levels, and higher blood levels of dihydroepiandrosterone tend to live longer than counterparts with normal readings.
Vastag B. A Clue to Long Life?. JAMA. 2002;288(11):1342. doi:10.1001/jama.288.11.1342-JHA20009-3-1