In Consumer Reports’ recent ratings of big-name diets — stalwarts such as Atkins, Ornish and Weight Watchers — the winner was Jenny Craig, a commercial program that combines personal phone or in-person counseling with a portion-controlled regimen of pre-made foods supplemented with homemade side dishes.

Four years ago, the winner was the Volumetrics diet, based on eating high-bulk, low-calorie food. In a sense, it’s still a winner: The Volumetrics brand is now part of Jenny Craig, which is why it wasn’t rated separately this time.

So should someone who needs to lose weight immediately sign up for Jenny Craig? While it’s obviously worth considering, it might not be for you if you don’t like the idea of eating prepackaged meals.

The diet that works is the one you can stay on. And these days, choices abound. You can follow the Ornish diet, a near-vegan plan with very little fat, or its diametric opposite, the Atkins diet, which allows almost two-thirds of your calories from fat. Or you can settle somewhere in between with the moderate regimens offered by Weight Watchers and Jenny Craig.

Consumer Reports’ overall scores of six diets were based on their adherence to nutritional guidelines and the results of published randomized clinical studies. Nutrition was based on an analysis of a week of menus from each book or program, using ESHA Research’s Food Processor software.

The Jenny Craig diet received CR’s top rating largely as a result of a recent 332-person, two-year study of the program published in the Oct. 27, 2010, Journal of the American Medical Association. In the study, 92 percent of participants stuck with the program for two years — a remarkable level of adherence. At the end of that time, participants weighed an average of about 8 percent less than when they started.

To help you decide which weight-loss diet is right for you, here are some basic realities:

Calories, with an asterisk

To lose weight, you have to burn up more calories than you take in. But emerging evidence shows that some forms of calories are more filling than others. Protein is the most satiating nutrient, followed by high-fiber grains, fruits, and vegetables.

It’s okay to go low-carb

Evidence is accumulating that refined carbohydrates promote weight gain and Type 2 diabetes through their effects on blood sugar and insulin. Moreover, clinical studies have found that an Atkins or Atkins-like diet not only doesn’t increase heart-disease risk factors but also actually reduces them as much as or more than low-fat, higher-carb diets that produce equivalent weight loss.

On the other hand, the Ornish Program for Reversing Heart Disease, which includes a low-fat diet along with exercise, stress management and group support, has proven so effective that Medicare now covers it for cardiac patients.

Support matters

Don’t discount the impact of a good emotional support system. The Jenny Craig diet, for instance, includes weekly counseling sessions, and group support meetings are the foundation of the Weight Watchers plan.

Copyright 2011. Consumers Union of United States Inc.