I have encountered the same problem. When you get older, your metabolism will decline, and a lot of calories will not be consumed and will accumulate into fat. So, first of all, strong oxygen exercise is necessary. Secondly, we should control the intake of carbohydrate and fat in our diet, eat coarse grains and high-protein foods as much as possible, keep 70% full at every meal, drink plenty of water, and the temptation of dessert can only be tolerated. In addition, we should strengthen some strength training according to our own situation, improve physical fitness and increase muscle content. The increase of muscle can effectively increase basal metabolism and ensure that you can consume calories when you are not exercising. If the conditions are good, you can go to the gym to consult a personal trainer and make a systematic muscle training plan. If the conditions are limited, you can do simple exercises such as sit-ups, push-ups and flat support at home.