Following bariatric surgery, a diet high in protein is preferable in an effort to maximize body fat loss and maintain lean body mass (muscle). A study published in the Annals of Internal Medicine on May 2004, showed that a high protein, low-carbohydrate diet does not promote higher weight loss but does promote higher body fat loss. During active weight loss, study participant's serum triglyceride levels decreased more and HDL cholesterol (good cholesterol) increased more.

Carbohydrates are the body's preferred energy source. By restricting carbohydrate intake, the body is forced to use your fat stores for energy. However, the American Heart Association guidelines should be kept in mind. Total protein should not exceed 100 grams a day. The selected protein foods should not contribute excess fat, saturated fat, or cholesterol. Total fat should be 30% or less of total calories, saturated fat should be 10% or less of total calories and cholesterol should be 200 mg or less per day.