Men who want to make their breasts flatter may do so because of significant breast development. The causes of breast enlargement in men can be divided into physiological and pathological causes. Pathological enlargement is generally caused by a pathological increase in estrogen in the body and requires a hospital visit for breast ultrasound as well as sex hormone levels and other tests to clarify the condition, and cannot be made flatter through exercise. Physiological enlargement refers to the accumulation of breast fat due to simple obesity, can reduce weight and promote health through the following exercise methods to achieve the purpose of making the chest flat: 1, fat reduction exercise: moderate, regular swimming, jogging, race walking, rope skipping, cycling, aerobics, dancing, ball sports such as basketball, soccer and other aerobic exercises, can increase the consumption of fat throughout the body, need to develop according to individual physical conditions Exercise plan; 2, the strength of the pectoral muscles training: such as barbell bench press, butterfly machine clip chest, equipment push chest, supine large flying bird clip chest, flat dumbbell bench press, up inclined plate dumbbell bench press, dumbbell flying bird and other movements, can be a good exercise to the pectoral muscles. If the action is not skilled, it is recommended to carry out under the guidance of a professional coach. In addition, exercise needs to be combined with diet to achieve a good fat loss effect. It is recommended to achieve a balanced diet with adequate intake of high quality protein such as eggs, milk, fish and fruits and vegetables. It is also necessary to reduce the intake of high-fat, high-calorie foods, to maintain adequate sleep and to develop regular habits of life.