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. A 15% loss of baseline weight occurred in 83% of patients on the rapid-loss diet and 48% of patients on the gradual-loss diet, a statistically significant difference.
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 gradual weight loss for safely shedding pounds in a randomized study with 120 patients.
“This study has shown that people who lose weight quickly are more likely to lose weight. It's the reverse of how we practice at the moment. 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.
The second factor is ketogenesis 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. “We believe that part of the reason why people in the faster-loss group had a lower drop-out rate is that they were not really hungry.”
When people lose weight, changes occur with several hormones, he explained. 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, and “by about the fifth week, their weight loss starts to level off,” he noted.
The study enrolled 120 obese but otherwise healthy people (average age, 51 years); nearly three-quarters were women. The average body mass index was 35 kg/m
The 60 patients randomized to the rapid-loss group received a diet that consisted entirely of commercially available, liquid food-replacement meals designed to produce a 1.5-kg loss each week. Patients randomized to the gradual-loss group received a combination of regular food and liquid meal replacements designed to produce a loss of 0.5 kg/week.
At the study's end, 50 (83%) of the rapid-loss patients and 29 (48%) of the gradual-loss patients achieved a loss of at least 15% of their starting weight, the study's primary end point, a statistically 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 statistically 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 statistically 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. We have a method [rapid loss] where patients can lose as much weight as with surgery, but they need pharmacotherapy” to maintain their loss, Dr. Proietto said in an interview.