Major Finding: Patients on a rapid weight-loss regimen designed to trim 1.5 kg/week had better adherence and greater weight loss than did patients on a gradual-loss regimen designed to produce a 0.5-kg/week loss.
Data Source: Single-center, randomized trial with 120 obese patients who began with an average body mass index of 35 kg/m
Disclosures: Nestle Australia provided free liquid food substitutes for the study. Ms. Purcell had no disclosures. Dr. Proietto has served on advisory boards for Nestle and Abbott.
STOCKHOLM — Fast weight loss worked significantly better than did gradual weight loss for safely shedding pounds in a randomized study in 120 patients.
“This study has shown that people who lose weight quickly are more likely to lose weight. The assumption that gradual weight loss is superior has no scientific basis,” Katrina Purcell said while presenting a poster at the meeting.
Ms. Purcell credited two factors for the success of rapid weight loss over more gradual loss. First, patient motivation. “The first 2 weeks are hard—but once they see the results, they want to keep going. Patients on the gradual-loss diet get disheartened,” said Ms. Purcell, a dietician at the University of Melbourne.
Second, ketogenesis is triggered by the very-low-calorie diet used for faster weight loss. “Part of the hypothesis was that ketogenesis would help rapid weight loss,” said Dr. Joseph Proietto, professor of medicine at the University of Melbourne and coordinator of diabetes, obesity, and endocrinology research.
“We believe that part of the reason why people in the faster-loss group had a lower dropout rate is that they were not really hungry,” Dr. Proietto said.
When people lose weight, changes occur with several hormones, he said. Ketones lead to release of cholecystokinin, a major satiety signal. When patients begin the rapid-loss diet, which is low in carbohydrates and fat, ketogenesis starts on day 2 and is in full effect by day 3 or 4. In contrast, ketogenesis never occurs in the gradual-loss group, he noted.
The study enrolled 120 people who were obese but otherwise healthy. Their average age was 51 years, nearly three-quarters were women, their average baseline body mass index was 35 kg/m
The 60 patients randomized to the rapid-loss group received a diet comprised entirely of commercially available liquid food-replacement meals, with their total daily calorie intake titrated to produce a 1.5-kg loss each week. Patients in the gradual-loss group received a combination of regular food and liquid meal replacements at a total energy level designed to produce a loss of 0.5 kg/week.
The rapid-loss regimen ran for 3 months, while the gradual-loss regimen ran for 9 months. Patients saw a dietician every 2 weeks during the study. The researchers designed both regimens to achieve a 15% loss of baseline weight.
At the end of the regimens, 50 (83%) of the rapid-loss patients and 29 (48%) of the gradual-loss patients lost at least 15% of their starting weight, the study's primary end point, a significant difference. For the entire study group, weight loss averaged 14% of starting weight in the rapid-loss arm and 9% of starting weight in the gradual-loss group, a significant difference. In the rapid-loss group, 59 of the 60 patients (98%) remained on their diet through the entire 3-month period, compared with 51 (85%) who stuck with the gradual-loss diet through 9 months, a significant difference.
The current study will follow patients for 3 years. In general, however, “once a patient loses weight, they are at the mercy of their hormone changes,” Dr. Proietto said in an interview. “There is no evidence that a person's weight set point changes with time.” Thus, drug therapy is the only reliable way to prevent regain in a person who has lost a substantial amount of weight, he added.