According to the rock band Metallica, “the brightest flames burn the fastest.” Inspiration for the lyric likely had nothing to do with human physiology. But it could be appropriate, as reported recently in the Journal of Clinical Endocrinology & Metabolism (2011; 96 [6], E972). Researchers found that individuals with higher metabolisms may have greater mortality risk. Out of 652 “healthy” Pima Indian volunteers, who did not have diabetes, 508 were measured for 24-hour energy expenditure, 384 were tested for resting metabolic rate and 240 were measured for both. During the study timeframe of 11.1 years, 27 of the subjects died from natural causes. Deeper examination of the data showed an association between higher 24-hour energy expenditure and resting metabolic rate, on the one hand, and death on the other. The study authors concluded that “higher metabolic rates predict early natural mortality, indicating that higher energy turnover may accelerate aging in humans.”