Six of the diets we looked at—Atkins, Jenny Craig, Ornish, Slim Fast, Weight Watchers, and the Zone—have all been subjected to the ultimate test: a clinical trial good enough to be published in a reputable medical journal. That means we don’t have to guess how well they work. We know.

And how well is that? In this, our third round of diet Ratings, the overall winner is Jenny Craig, the widely-advertised commercial program that combines personalized motivational counseling with a meal plan consisting of its branded single-serving entrees and snacks, supplemented with sides and beverages you supply yourself.

But that doesn’t necessarily mean it’s right for you. That’s because the best diet is the one you’ll stick with, and different diets appeal to different people. So the real trick is to find one the matches your preferences. For example, Jenny Craig might not be a good fit if you don’t like the idea of having to buy (or eat) prepackaged meals.

And just to be clear, we didn’t conduct these clinical trials ourselves, as we’re not a biomedical research institute. Instead we scoured the scientific literature, and our in-house data scientists crunched the numbers to come up with Ratings for each diet’s long- and short-term weight-loss results and dropout rates. Meanwhile, our food experts analyzed menus from each diet for the other critical piece of the Ratings—nutritional quality. (We also rated one additional diet, Nutrisystem, based just on nutrition.)

For details, including nutritional information, complete ranking, and descriptions of the features that can help you decide which diet is right for you, see our diet Ratings.