Most Effective Diets for 2011

As millions seek to ditch the holiday flab, The Daily Beast analyzes the most up-to-date clinical studies on 10 major diets for our second annual ranking of weight-loss effectiveness.

If your list of New Year’s resolutions includes weight loss, you should know that all diets are not created equal. With the promise of fast weight loss comes faster weight regain, just as eliminating entire food groups increases the chances of giving up altogether. So, what diet really works?

In 2010, dieters didn’t even have to chew, as juice cleanses and the baby food diet, both popularized by celebrities, caused many to shun solid food for fast weight loss. Another fad diet best left undone: the junk food diet. Designed by a nutrition professor at Kansas State University, the diet consisted of Twinkies, Ho Hos and Doritos and left him 27 pounds lighter after two months. Even the effectiveness of exercise was called into question.

To once again try to clarify all the conflicting information on weight loss, The Daily Beast revived a resolution from last year involving the latest scientific proof: Let’s figure out, as definitively as possible, which diets really work.

For our second annual ranking of the most effective diets, we took the largest, most recent clinical studies for the nation’s most popular diets, and compared the raw data using consistent criteria: six-month and 12-month figures for weight loss and participant retention, as well as 12-month change in body mass index. For 2011, we added clinical results published in 2010. (The last time, as best we can tell, that anyone undertook a similar exercise was back in 2007 by Consumer Reports, but they did not measure for BMI changes.) In doing so, we were able to find some clear differentiations in terms of which of 10 popular diets work better than others.

The answers were surprising. Mainstays like Jenny Craig and the Zone fared relatively poorly, while Weight Watchers and the Mediterranean diet did well. “To me, a diet is something that you count the days until it’s over and you miss the big picture,” says Dr. Connie Guttersen, nutritionist and author of The Sonoma Diet, and the new update The New Sonoma Diet, released this year. Guttersen says a diet should instead be “a way of eating that becomes a lifestyle.”

Experts agree that the most effective diets are feasible over an extended period of time, but there’s not a single solution for the entire population. “What I believe makes a diet ‘effective’ is that you can stay on it and that your body feels good on it. This will not be the same for each person,” says Brooke Castillo, a weight-loss coach and author of Why Can’t I Lose Weight? “Any diet that makes you feel hungry (liquid shakes) or tired (Atkins) may work temporarily, but won’t last long-term because they put you at war with your own body… cooperation with our bodies is what lasts.”


To compile our rankings, we combed journals of medicine and nutrition and university publications to find clinical studies on specific diets that included six-month and 12-month figures for weight loss and participant retention, as well as 12-month change in BMI. Each category was equally weighted at 20 percent of the total rank for each diet. In instances where one category was unavailable, the remaining categories were weighted at 25 percent. If a new clinical study for a diet was published this year, we updated the efficacy of the diet by averaging results with earlier studies.

Additionally, while we didn’t include nutrition in the ranking calculation, we recorded the dietary quality of diets when available, based on the clinical study “A Dietary Quality Comparison of Popular Weight-Loss Plans, “ published in the Journal of the American Dietetic Association in October 2007.

In an effort to keep the data as consistent as possible, some popular diets, such as the South Beach and Abs diet, are absent from the list due to lack of published, long-term clinical studies.

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