Of six popular diet plans, the Jenny Craig diet program seems to be the best for weight loss and adherence, according to a new ranking released today (May 10) by Consumer Reports.

The Jenny Craig diet program , which involves eating prepackaged meals with homemade sides, bested the Slim Fast, Weight Watchers, Zone, Ornish and Atkins diets, according to the Consumer Reports article.

Consumer Reports largely based its ranking decision on a study published last year in the Journal of the American Medical Association. That study, which lasted two years and included 332 people, showed that 92 percent of study participants stuck with the diet for two years and lost an average of eight pounds.

The finding is not that surprising because research shows prepackaged foods help people with portion control , said Stella Volpe, a registered dietitian and professor and chairwoman of the Department of Nutrition Sciences at Drexel University in Philadelphia.

"So if you're looking for something like that, then that's going to work," Volpe told MyHealthNewsDaily.

The only drawbacks of the Jenny Craig diet are that people are limited to what prepackaged foods are included in the diet program , and some foods may have more preservatives than what you might make yourself, she said.

The Consumer Reports researchers also noted the Jenny Craig diet may not be best for everyone, depending on whether people like to cook their own foods or eat prepackaged foods.

Low-carb diets

But just because Jenny Craig ranked higher than some of the other diets reviewed, doesn't mean those diets aren't also effective, the new report said. For example, the Ornish diet is a near-vegan diet that includes very little fat, and the Atkins diet is a high-fat, low-carb diet that allows nearly two-thirds of the diet to come from fat.

However, Volpe warned, low-carb diets can be hard to stick with because carbohydrates provide energy for our bodies and so much of our calorie intake comes from them.

"Carbs are not bad for you, it's the amount and the type that people choose," Volpe said. "A lot of people will eat things like donuts and those types of things, or white bread, as opposed to whole grain breads. And people tend to overeat carbs in general, so their total caloric intake is higher."

Carbohydrates are necessary for proper brain functioning and body sugar storage, she said.

What's in a calorie?

But in the end, the main idea of a diet is to burn more calories than a person takes in, according to the Consumer Reports article, and not all calories are alike. Protein is the most satisfying of all the nutrients, followed by grains that are high in fiber, vegetables and fruits.

"We used to believe that it was the same if you ate 200 calories of a cream puff or 200 calories of a chicken breast," registered dietitian Karen Miller-Kovach, chief scientific officer for Weight Watchers, said in the Consumer Reports article. "But people would ask, 'Why do I feel hungry sooner after eating the cream puff?'"

Weight Watchers unveiled a new point system late last year that takes this concept of "more-filling calories" into account, according to Consumer Reports, but clinical trials evaluating the new system were not available in time for the rankings.

Pass it on: Consumer Reports ranked the Jenny Craig diet program first out of six popular diets for weight loss and adherence.

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