Some recommend that it has to be really vigorous in order to help but few people can maintain this for long. However, there is no disagreement at all about the benefits of exercise for health and to counter the risks of being obese or overweight. In fact, many women gain an average of 5 pounds after menopause.5 Lower estrogen levels may play a role in weight gain after menopause. But weight gain may be caused by your metabolism slowing down as you age, less-healthful eating habits, and being less active. You also lose muscle mass as you age, so you use fewer calories.