Diets Work if People Stick to Them, Study Finds
As hard as dieting can be for some people, new research suggests that diets work as long as people stick to them. According to the team, there are very small differences between the effectiveness of branded or trademarked diets. The key is to adhere to the diet's guidelines.
"We wanted to be the first to compare, in an evidence-based fashion, all existing randomized trials of branded diets to determine their effectiveness with regard to weight loss," explained the lead author of the study, Bradley Johnston, an assistant professor of clinical epidemiology of the Michael G. DeGroote School of Medicine at McMaster University and clinical epidemiologist and scientist at The Hospital for Sick Children (SickKids).
For this study, the researchers conducted a meta-analysis on 48 randomized clinical trials done on branded diets. Some of these diets included Atkins, Weight Watchers, Zone, Jenny Craig, LEARN, Nutrisystem, Ornish, Volumetrics, Rosemary Conley, Slimming World and South Beach. The trials totaled more than 7,200 adults who were overweight or obese. They had a median age of 46. Weight loss progress was assessed at six months and then again at 12 months.
At the six-month mark, the researchers calculated that the participants following low-carbohydrate diets lost 19 more pounds than people who were not on any diets. Participants on low-fat diets lost 17 more pounds than people who did not diet. By the 12-month mark, the researchers reported that the two-pound difference between the two diets was gone.
"Given the popularity of these diets around the world, there has been a real lack of research to examine their relative benefits. But overall, the differences between the different diets regarding their impact on weight loss were relatively small," researcher Geoff Ball, associate professor and an obesity expert in the Faculty of Medicine & Dentistry at the University of Alberta, said according to the press release.
The team did find that diets that included behavioral counseling boosted weight loss by seven pounds at six months. Diets that incorporated exercise helped improve weight loss by four and a half pounds at the end of 12 months. The researchers stated that looking into the long-term effects of these diets on weight loss could help them better assess the effectiveness of branded diets versus trademarked ones.
The study was published in the Journal of the American Medical Association (JAMA).