Clinical efficacy of a medically supervised outpatient high-protein, low-calorie diet program is equivalent in prediabetic, diabetic and normoglycemic obese patients

OBJECTIVE: Type 2 diabetes mellitus (T2DM) affects approximately 10% of Americans, while 79 million Americans are estimated to have glucose intolerance or prediabetes (pre-DM). The present study was designed to determine whether obese patients with pre-DM or T2DM would lose weight as effectively as obese normoglycemic patients, in a medically supervised high-protein, low-calorie-weight management program. METHOD: Patients enrolled in a self-paid, university-based, outpatient weight loss program using prescribed very-low-calorie diet (VLCD) (500–800 cal per day) or LCD diet (800–1200 cal per day), recommended exercise and group behavioral counseling were studied retrospectively. Patients entering the program for the first time and attending weekly clinic visits for more than 4 weeks were included in the analysis. RESULTS: A total of 2093 obese patients, of whom 583 patients with pre-DM (fasting glucose ⩾100 and <126 mg dl(−1)), 367 patients with T2DM and 1143 normoglycemic patients entered the program from 1991 to 2010, who met all the inclusion criteria were included in the analysis. The body weight at baseline was 104.0±20.0 kg for DM, 101.4±18.4 for pre-DM and 99.0±18.8 kg for non-DM. Weight loss and percent of weight loss within 12 months were analyzed using a linear mixed-effects model. There was no significant difference in weight loss between DM vs non-DM (P=0.4597) and pre-DM vs non-DM (P=0.6006) in 12 months. The length of enrollment in the program was positively correlated to weight loss rates in all patients (P<0.001). CONCLUSION: This study demonstrates that obese, pre-DM and DM patients all lost weight as effectively with VLCD or LCD over 12 months. Given the impact of weight loss on the progression of comorbid conditions, these data support the hypothesis that medically supervised diets, including VLCD and LCD, should be more widely used in the prevention and treatment of obese patients with pre-DM or T2DM.