A multicenter evaluation of a proprietary weight loss program for the treatment of marked obesity: a five-year follow-up.

OBJECTIVE: The traditional goal of obesity therapy has been the reduction of body weight to an ideal standard. Patient difficulties, however, in reaching this goal have led to a reassessment of weight loss criteria. The Institute of Medicine of the National Academy of Sciences recently proposed that successful long-term weight loss be defined as the reduction of initial weight by 5% or more and the maintenance of this loss for at least 1 year. The present study used these criteria to evaluate the long-term efficacy of a proprietary weight loss program.
METHODS: Patients were 621 persons who had completed a 26-week weight loss program that included 12 weeks of treatment by a very-low-calorie diet. They were recruited from a total of 1,283 eligible persons who had been treated at 36 clinics nationwide. Clinics were randomly selected to participate. Patients' weights were determined in telephone interviews initially conducted 2 years after treatment and then at yearly intervals through 5 years of follow-up.
RESULTS: At the end of treatment, men achieved a mean reduction in initial weight of 25.5 +/- 1% and women 22.6 +/- 1%. Subjects regained substantial amounts of weight by the 2-year follow-up but 77.5% of men and 59.9% of women still maintained losses of 5% or more of body weight. At the 3-year follow-up, 53% of the original sample (of 621 persons) maintained losses of 5% or more and 35% losses of 10% or more. These trends were apparent 4 and 5 years after treatment but the dwindling sample sizes prevented definitive assessments. DISCUSSION: The findings showed that a program of lifestyle modification combined with the brief use of a very-low-calorie diet was associated with successful weight control in a substantial portion of patients several years after treatment. Long-term weight losses of 5% or more of initial weight are likely to be associated with improvements in health complications.