The fullness of the cheeks depends of multiple factors like facial structure (facial bones, soft tissues) genetics, diet, environmental factors, etc. The amount of fat in the cheeks has a correlation with the body content of fat (% of total body fat). Therefore, unless the body fat content is low, the fat of the cheeks won't decrease.Patients interested in decreasing the fullness of their cheeks without surgery but with diet and exercise should make a consultation with a licensed professional nutritionist and physical trainer specialized in changing body fat content (usually for body building competitions). In my practice, patients interested in these type of non-surgical body change are usually referred to a licensed professional nutritionist and physical trainer