With naturel way if you loose waight, breast will loose waight but they will become loose and dangling. Best answer is reduction surgery. I assure you you will never regrate it

Dietary restriction and physical workout will reduce the fat content of the body, but certain body sites are more prone to deposit fat, like breasts. Food with low glycemic index and less fat/ oil content should help. Workout at gym under a trainer can help in redistribution of fat. For further help you may contact in private consultation.