Boys with big chests may be related to over-obesity, pathological increase in estrogen, etc. The methods of flattening include diet control, exercise conditioning, and surgical treatment. 1. Too obese: If men are too obese, it will lead to the accumulation of fat content in the chest, making the chest look fat. In this case, you need to reduce the fat content of the chest, usually avoid eating foods with high fat content and high protein, increase exercise and actively reduce weight. You can also reduce fat by doing push-ups and lifting dumbbells. 2. Pathological increase of estrogen: If it is caused by pathological increase of estrogen, it is difficult to improve breast shape through exercise and weight reduction. Liposuction surgery can be used to extract the excess fat particles inside the breasts to achieve the effect of flat chest. Boys with large breasts can go to the breast surgery department to clarify the cause of large breasts, and then strictly follow the doctor’s instructions to carry out the corresponding treatment.