A new study suggests that having higher muscle mass could be linked to a lower risk of diabetes. The finding that more muscle mass is beneficial is consistent with what's already known about muscle, fat and metabolism, said Daniel Rubin of the School of Medicine's Division of Endocrinology. "Extra fat has bad effects, but more muscle has good effects. These data are also consistent with data we see on exercise, that it helps decrease diabetes risk, and that a lack of exercise and weight gain increase risk," he said.