The lifestyle intervention using protein supplemented very low calorie meals will be implemented with individual counseling sessions for 12 months. Initial intensive weight loss stage will be delivered during the first 4 month period with total meal replacement to partial meal replacement using protein supplemented very low calorie meals. During the weight loss maintenance stage, regular intermittent very low calorie meal replacement one week per month will be delivered for the entire period. Mobile counseling will be offered to help patients achieve weight loss as well as weight loss maintenance.

The conventional low calorie diet program will be offered to participants assigned to control group using educational material and individual counseling sessions for 12 months. Mobile counseling will be also offered for weight loss and weight loss maintenance.

Protein supplemented very low calorie meal is a shake-type meal replacement with total calories of 600 to 800 calories per day and proteins provided at 1.2g of ideal body weight per day. The four-month, very low calorie diet program schedule will be as follows. In the first two weeks, all three meals are replaced, followed by two meals replaced and one meal in food in the next six weeks, and one meal replacement is recommended for the next eight weeks. For the next eight months, the intermittent very low calorie meal replacements will be provided regularly for one week a month. If a subject gains weight more than 2kg, he or she will have an additional 1 week of two meal replacements, and if a subject gains weight more than 4kg, he or she should have an additional 2 weeks of replacement.

Individual sessions will be held 11 times during the study. Mobile counseling with dietitians or nurses will be offered to help subjects lose weight and maintain weight loss.

Changes of weight loss from the baseline expressed as kg

Changes in muscle mass and fat mass from the baseline expressed as kg using bioelectrial impedance analysis (Inbody Co., Seoul, Korea)