(Medical Xpress)—Anyone who wants to lose weight has a wide variety of diets to choose from, but knowledge of what works is often poor. Researchers at Karolinska Institutet and Uppsala University have now evaluated a Swedish commercial weight loss programme called Itrim, and found it to be effective. After one year, participants had lost 11 kg on average.
"Most of the participants lost a lot of weight in the first three months and then showed very good weight stability after one year," says Erik Hemmingsson, researcher at Karolinska Institutet and Karolinska University Hospital's Obesity Centre. "However, we still don't know what happens in the longer term. Maintaining the lower weight is without a doubt the greatest challenge for dieters."
Itrim is based on available research on sustained weight loss through diet and exercise. Each participant selects one of three diets at the start of the at a minimum one-year programme: a very low calorie diet (VLCD, 500 kcal/day consisting solely of meal replacements for 6-10 weeks); a low calorie diet (LCD, 1200-1500 kcal/day consisting of a mix of normal food and meal replacements); or a calorie-restricted normal food diet (1500-1800 kcal/day). The program also consists of group sessions, individual booster sessions and exercise. People wishing to go on the most rigorous VLCD programme are required to see a physician at the start in order to minimize adverse events.
The effectiveness of the programme was evaluated by measuring weight loss in 9037 participants after one year. The mean age was 48 and the majority of the study participants were women. Forty-two percent chose the VLCD diet, 51 percent the LCD diet, and seven percent the calorie-restricted normal food diet.
The study, which is published in the scientific journal American Journal of Clinical Nutrition, found that the overall weight loss was 10.9 kg (or 12 percent of the starting weight) after one year. The participants on the VLCD programme lost most weight, on average 13.8 kg (or 14 percent of the starting weight). The LCD and calorie-restricted normal food diet participants lost 8.9 kg (10 percent) and 7 kg (8 percent) respectively.
Twenty-one percent of all participants dropped out of the programme. The lowest dropout rate was seen in the VLCD group (18 percent), followed by the LCD group (23 percent) and the restricted diet group (26 percent). Risk factors for dropout included low age, low starting BMI and low initial weight loss.
Participation in the Itrim programme costs about SEK 9000 a year (about $1300, ¬1000). According to Dr Hemmingsson, healthcare services in Sweden lack resources to help overweight and obese people lose weight, which is a problem.
"Many overweight people therefore turn to commercial programs, where the effects often are unclear," he says. "So we really need to evaluate commercial weight loss programmes."
More information: Erik Hemmingsson et al., Weight loss and dropout during a commercial weight loss program using VLCD, LCD and restricted normal food: observational cohort study. American Journal of Clinical Nutrition, online ahead of print 19 September 2012. ajcn.nutrition.org/content/early/2012/09/17/ajcn.112.038265.abstract?sid=addbdc9a-f9e6-4628-ae73-58c6d7de4f6e