You've been fit and trim your whole life, but ever since you turned 40 or 45, you gained an unexpected amount of weight. What's more peculiar is that you didn't even change your nutrition or your exercise habits. The weight seems to have come over night. What's going on here?
If you're a woman, your estrogen has been declining since about the age of 35. Fortunately for your body, fat cells produce estrogen as well. So as estrogen levels fall, fat cells multiply in order to provide you with the missing estrogen. In fact, some weight gain during menopause is actually desirable. Women who gain a modest amount of weight (10 pounds or less) during menopause have fewer hot flashes, better skin, better hair, better sleep, and many other benefits.
But if you gained more than the 10 pounds, what can you do to drop that extra weight? First and foremost, you have to address your diet. No matter how much you exercise, if your diet is not in place, you can forget about losing those pounds. There is nothing particularly exotic about a diet for menopausal women. The things that were good for you before menopause are still good for you now.
Assuming that your diet is taken care of, you have to do at least 4 hours per week of aerobic activity (like walking, biking, swimming, skiing, etc.). You see, dieting can only decrease the number of fat-storing enzymes that you have. It can't actually increase the number of fat-releasing enzymes that you have. Only exercise can do that. So exercise becomes particularly important during this time.
In addition to the aerobic activity, you should complement that with resistance training. Resistance training may not directly help you lose weight, but it has plenty of other benefits that aerobic activity can't offer. For one thing, it helps strengthen your bones, which prevents osteoporosis. Additionally, it helps balance blood sugar much better, and just plain makes you look better. So ladies, don't be afraid to lift weights.
And gentlemen, you may have noticed that after 40, you start to accumulate more fat around your chest. That is caused by rising estrogen levels. You may decide to counteract that with increasing amounts of cardio, and I have to advise against it. Doing excessive amounts of cardio can paradoxically make you store fat, rather than release it (it's a fairly complex reason, but if you're curious, please get in touch with me, and I'll explain). However, through strength training, you can raise your testosterone and growth hormone, thereby shifting your testosterone:estrogen ratio more in your favor.
But just because you're weight training doesn't mean that you're off the hook from a good diet. First and foremost, get your diet taken care of before worrying whether your exercise is optimal. In the presence of a junk diet, even with perfect exercise, you will not help your situation.