A 54-month evaluation of a popular very low calorie diet program.

BACKGROUND: Thirty-three percent of the adult American population over the age of 20 is obese. Many attempts to treat this increasingly occurring problem have had poor results. Both achieving weight loss and maintaining weight loss are difficult; however, current treatments appear more effective in achieving weight loss than in maintaining weight loss. The current study followed a cohort of patients to analyze weight maintenance and predictors of weight maintenance in a 26-week, formula-based, very low calorie diet program.
METHODS: The study population consisted of a consecutive sample of 145 overweight patients who entered a very low calorie diet program and were contacted at 54 months after program entry.
RESULTS: For men, the average initial weight loss at program termination was 27.2 kg (22% of original weight) and for women, 19.3 kg (18.8% of original weight). At 54 months after program entry, the average maintained loss was 5.1 kg (4.3% of original weight), at a cost of $630 per kg of long-term weight loss. There was no significant difference in maintained weight loss between men and women. Twenty-six percent of patients maintained a medically significant weight loss of 10% of entry weight. Subjects who exercised regularly maintained an average of 9.6 kg compared with 1.3 kg for nonexercisers. Those who attended the program for a longer period, and exercised more, maintained their weight better. The 54-month weight loss was similar to that seen at 30 months but markedly less than that at 18 months.
CONCLUSIONS: Very low calorie diet programs have limited long-term success that may not justify the risk of adverse effects and high costs. Longer program attendance and continued exercise are associated with improved weight maintenance. Evaluation of dietary programs should be based on a sample of consecutive patients followed for a minimum of 2 years after program completion.