At menopause, the typical female fat distribution gives way to storage of fat around the waist and an inability to lose weight using tactics that were successful before the hormonal shift.
Estrogen is a potent insulin-sensitizer and estrogen and progesterone together are anti-cortisol agents. So, the female hormone profile (estrogen and progesterone balance) is key in decreasing weight gain, making weight loss easier and maintaining the hourglass shape. Menopausal women are more insulin resistant, more stress responsive, and in addition to the decreased levels of estrogen, the ratio of estrogen to progesterone the ratio is often even more out of balance (more estrogen relative to progesterone compared to what it was).
Want to learn more? Check out this detailed blog on the issue: http://www.metaboliceffect.com/menopause-weight-gain/