There are many ways for obese boys to lose fat, including exercise and diet. In terms of diet, we can try to control calorie intake, reduce foods with high calorie, high fat and high sugar, and increase the intake of vegetables, fruits, whole grains and other foods. In addition, the intake of protein can be appropriately increased, such as chicken breast and fish. In sports, you can choose a combination of aerobic exercise and strength training, such as running, swimming and fitness.