It depends on the way to lose weight. The breast is located in the superficial fascia of pectoralis major, and its structure is mainly composed of mammary gland, blood vessels, nerves, connective tissue and adipose tissue. By losing weight, the breast, blood vessels and nerves of the breast generally do not change much, only the pectoralis major closely related to the breast, as well as the adipose tissue and connective tissue in the breast. ...