Purpose: To evaluate a year-long behavioral weight control program, used with and without an intermittent very-low-calorie diet (VLCD) in the treatment of type II diabetes mellitus.
Patients and methods: Subjects (n = 93) were randomly assigned to 50-week treatment programs that used either a balanced low-calorie diet (LCD) of 1,000 to 1,000 kilocalories (kcal) per day throughout or included 2 12-week periods of a VLCD of 400 to 500 kcal per day alternating with the balanced LCD. Weight, glycemic control, blood pressure, and lipids were assessed at baseline, at the end of the year-long treatment, and at 2-year follow-up.
Results: Subjects in the VLCD program lost significantly more weight than did LCD subjects at the end of the 50-week program (14.2 kg versus 10.5 kg; P = 0.057) and remained off diabetes medication longer (P < 0.05). These benefits of the VLCD were due primarily to the first 12 weeks of the diet; the second diet maintained, but did not increase, these effects. Subjects in both groups experienced marked improvements in glycemic control and cardiovascular risk factors over the year-long program, but attendance declined in the latter weeks of treatment and weight was regained. There was also marked recidivism in both groups in the year following treatment.
Conclusions: The intermittent VLCD improved weight loss and glycemic control, but these effects were quite modest and do not appear to justify the clinical use of an intermittent VLCD. Moreover, lengthening treatment to a full year did not prevent relapse. Thus, further research is needed to develop a successful approach to long-term weight control.