Because you are weak, you'd better exercise step by step, and don't rush into it, or you will get hurt easily. You can start jogging for 30-40 minutes every day, that is, try not to stop in the middle. You can walk in the middle if you can't keep up with your physical strength at first. After a while, it shows that your physique has improved obviously, and then set the running time at 45 minutes a day, and gradually become a medium-speed running, but don't.

According to the above amount of exercise, you should have a good appetite. Just remember to eat a balanced diet. After all, you are thin, you don't have to worry too much about your diet like a fat man, but you'd better stay away from junk food as much as possible.

As long as you keep exercising every day, your physical fitness will be improved, and your body naturally needs various substances to supplement it, so your appetite will be good and your body will be stronger.