Ah, diet crazes. First it was Atkins, then it was Dukan, now it’s this: The 17 Day Diet, an eating plan based on—you guessed it, 17-day cycles—that has raced to the top of The New York Times bestseller’s list. Curious about the buzz behind this doctor-authored weight-loss tome? (If only for dinner party conversation?) We were, too. Though it turns out, you might already be familiar with the book’s message.
Dr. Mike Moreno, a family care physician from San Diego, based the plan on an idea he’s calling “body confusion,” i.e., tricking your body into keeping metabolism constantly up-up-up by not letting it get too used to any one eating pattern. By switching up the types of proteins, carbs, etc., you eat every 17 days (as well as changing around your calorie counts), Moreno claims you keep the body guessing. And that 17-day marker is based on how long he says it takes your body to fall into a pattern.
The Actual Practice
The diet is broken into four, 17-day phases. Phase one, or “accelerate” is aimed at rapid weight loss—achieved by cutting calories down to around 1,200 per day. (Moreno claims that people can expect to lose up to 15 pounds during this first phase.) Phase Two, or “activate” is about losing yet more weight, albeit less rapidly, by alternating between higher and lower calorie days. Phase Three, or “achieve” is about reintroducing certain foods, and Phase Four, or “arrive,” is the ongoing, maintenance phase. A few constant no-no’s throughout are starchy carbs or fruit after 2 p.m.
We’re skeptical. Moreno himself cops to the fact that a lot of the weight loss in the beginning of the diet is water weight. And many experts discount his concept of body confusion altogether. “There is no proof that metabolism mixing will help [with weight loss],” Marisa Sherry, R.D., told CBS News. But the idea of cutting calories, coupled with the fact that the diet promotes clean eating and exercise, Sherry said, should help people lose weight. So really, isn’t it just stuff we’ve known all along? —Catherine Pearson