This may be because of adolescence, when people always get fat. You can exercise properly, eat reasonably (don't go on a diet, it will rebound), eat less snacks and fast food, cook your own meat if you want, stew it and add vegetables and other accessories. If you are greedy for tomatoes or pure dark chocolate (bitter, you will lose weight if you eat less), you can go to school by bike, not too slow and ineffective, but not too fast and dangerous.

Vegetarian, eat breakfast, defecate every day and drink plenty of water.

Keep a good attitude, don't worry, don't try to lose weight because of others' ridicule. If you don't talk about your health, it will be difficult for you to concentrate and your grades will drop.

Physical education class should also actively go to the gym. If possible, you can jog for 30 minutes at night or in the morning (less than 20 minutes doesn't matter). On weekends and holidays, parents can take them to the gym for proper exercise (choose some exercises they can afford, such as running and skipping rope). Go out for a walk after class, don't always sit.