Men who want to flatten their breasts may do so because of obvious breast development. The causes of male breast enlargement can be categorized into physiological causes and pathological causes. Pathological enlargement is generally caused by a pathological increase in estrogen in the body, you need to go to the hospital to do breast ultrasound and sex hormone levels and other tests to clarify the condition, and can not be flattened by exercise. Physiological enlargement refers to the accumulation of breast fat due to simple obesity, you can reduce weight and promote health through the following exercises to achieve the purpose of flattening the chest: 1, fat loss exercise: moderate, regular swimming, jogging, walking, jumping rope, cycling, gymnastics, dancing, ball games such as basketball, soccer and other aerobic exercise, can increase the body’s fat consumption, need to be based on the individual’s physical condition to formulate Exercise program; 2, pectoral muscle strength training: such as barbell bench press, butterfly machine chest clamp, instrument push chest, supine big bird chest clamp, flat dumbbell bench press, upward inclined plate dumbbell bench press, dumbbell bird and other actions, can be very good exercise to the pectoral muscle. If the movements are not skillful, it is recommended that they be carried out under the guidance of a professional trainer. In addition, exercise needs to be combined with diet to achieve good fat loss. It is recommended to do a balanced diet, consume enough high-quality protein such as eggs, milk, fish and meat, as well as fruits and vegetables. It is also necessary to reduce the intake of high-fat, high-calorie foods, maintain sufficient sleep, and develop regular habits.