Slower Metabolism – Your metabolism is how many calories you burn without taking the time to do any exercise, so through the act of living on its own. People with high metabolisms burn through any food they eat much faster than those with low metabolisms. The metabolic rate slows down considerably as you get older and as you’re burning fewer calories this generally causes some weight gain.
Muscle Mass – After the age of thirty your muscle mass will start to naturally shrink. This can lead to weight gain on its own but it will also lessen your metabolism as muscle burns much more calories than fat does.
Menopause – Obviously not a factor for men but a considerable one for women. During menopause you’ll produce much less oestrogen. The body’s response to this is to retain fat as oestrogen can be pulled out of fat cells, this leads to you gaining some belly fat!
Sedentary Lifestyle – As you get older you tend to be less active than you once were. This will simply increase the decline of your metabolic rate.
Stress – Having a hectic or stressful lifestyle can have a massive contribution to your midlife weight gain. Stress can lead to stress eating which will obviously help pile on the pounds.