Researchers at Harvard Medical School and the National Institute on Aging found that resveratrol in high doses let mice eat a high fat diet yet avoid health problems commonly associated with obesity. The liver and other systems of these obese mice remained healthy and fat-related deaths dropped 31% for mice fed resveratrol. Another study showed less weight gain in mice fed resveratrol, greater physical endurance, and better insulin sensitivity. Resveratrol also demonstrated the ability to increase life span in yeast, mice, and certain fish.