Fueling is Different for Males and Females

From NY Times

Why women respond differently seems obvious. Women are, after all, awash in the hormone estrogen, which, some new science suggests, has greater effects on metabolism and muscle health than was once imagined. Some studies have found that postmenopausal women who take estrogen replacement have healthier muscles than postmenopausal women who do not. Even more striking, in several experiments, researchers from McMaster University in Canada gave estrogen to male athletes and then had them complete strenuous bicycling sessions. The men seemed to have developed entirely new metabolisms. They burned more fat and a smaller percentage of protein or carbohydrates to fuel their exertions, just as women do.