Insulin resistance. At the same age, women are more likely to have higher bmi than men. If the bmis were the same, the major factor to account for differences would be sex related hormones. Since women clearly become more Insulin resistant (ir) after menopause, it seems that Estrogens protect against Insulin resistance. With the more dramatic decline in hormone levels in women, it is likely they have more ir.
No. Insulin resistance can be genetic component but has no bearings on gender. Bmi has strong correlation.