Diet Plans Have Similar Results, but Commitment Is Hard, Study Finds
Dieters lost similar amounts of weight on four popular diet plans that use different weight-loss methods, but just 25% of adults were able to follow the plans closely for a full year, according to a study published Wednesday in the Journal of the American Medical Association, USA Today reports (Hellmich, USA Today, 1/5). The study, led by Michael Dansinger of the Tufts-New England Medical Center, involved 160 overweight or obese adults ages 22 to 72. The participants were split into groups of 40 assigned to one of four diet programs: the Atkins diet, which reduces carbohydrate consumption; the Zone diet, which aims to create an eating plan that is 40% carbohydrates, 30% fat and 30% protein; Weight Watchers, which uses a point system to restrict calories; and the Ornish diet, a mostly vegetarian diet that limits fat consumption to 10% of calories.
Participants received counseling on their respective plans for two months and then were instructed to continue the diets on their own for 10 months (Mishra, Boston Globe, 1/5). Weight and heart disease risk factors were measured at intervals of two, six and 12 months. The study's findings include the following:
- About 50% of participants stopped the Ornish and Atkins plans within one year, while 35% quit the Weight Watchers and Zone plans;
- About 25% of dieters in each group followed their plans very closely for one year;
- One-quarter of participants in each group were able to lose 10 to 20 pounds and keep it off for the year, while about 10% of participants lost 10% of their body weight and kept it off throughout the study;
- Participants who lost 5% of their weight had a 10% decrease in risk factors for heart attack; and
- Participants on the Ornish diet were able to lower their LDL -- or bad cholesterol -- the most, while those on the other plans had the biggest increases in HDL, or good cholesterol (USA Today, 1/5).
Dansinger said, "The idea that there's one best diet for everyone is becoming an old-fashioned notion" (Boston Globe, 1/5). He added, "To find one that's best for you, try dating the diets as if you are looking for a lifelong partner. You may have to kiss a few frogs along the way, but once you find the one you can live with forever, stand by your plan" (USA Today, 1/5).
Harvard University nutrition professor Frank Sacks -- who is leading a larger, similar study -- said, "You hear claims that one diet is better than the others, but this study shows they're the same," adding, "The quality of diet research is terrible. People can advocate diets and supplements for doing this or that, and there's absolutely zilch to support them" (Boston Globe, 1/5). The study is available online.