Is putting on weight inevitable in middle-age or after menopause?
The fact is, many people do put on a spread as they reach middle-age or menopause. Are there changes in hormonal balance that cause weight gain? Is the process of sarcopenia (loss of muscle, gain of fat) inevitable? Is there some biological process that causes a thicker, heavier frame as the years go by?
Physically slowing down is far more likely to be the cause. As most people age, they tend to have more aches and pains, are more easily injured, and tend not to push themselves physically as hard. This boils down to doing less exercise. Our society expects us to slow down as the years go by - older people tend to spend less time doing any kind of exercise.
Study after study has found that older people who exercise regularly and sufficiently can maintain their figures. The hormonal changes that occur in women with menopause need not lead to overweight. Rather it is lifestyle (exercise, calories, alcohol and poor diet) that is the underlying cause in middle-age. I have several male and female acquaintances in the weights room at my gym in their 60's, 70's and 80's who have the muscle bulk and figures to disprove the myth that age leads to fat.
If you are going to exercise for the rest of your life, it has to be enjoyable and invigorating. Find an activity, sport, task or exercise that makes you happy, that is engaging and fun. If you do it on your own, that is OK. If it is with people, enjoy their company, and do not compete.
You are never too old to start. In fact, the greatest benefits from weight training are among the elderly. You can start with weights as light as your water bottle.