Description: The program involves making lifestyle changes that incorporate three areas: a healthy relationship with food, physical activity, and balance and motivation in your life as a whole. Participants can sign up in person, by phone, or online; prepared meals and snacks are the core of the program. Participants are given a customized plan built for them with the assistance of a "personal consultant" who coaches clients through their weight loss, as well as three meals and up to three snacks per day to be accompanied by fresh fruits and vegetables. The company says its meals teach clients about eating a nutritious, balanced diet that is high in fiber and moderate in fat and sodium.
Studies show: People who stick with the Jenny Craig plan lose considerable weight, according to Consumer Reports, but a study involving Jenny Craig client histories showed a high dropout rate. A clinical trial that followed program participants had better results.
Experts say: Since long-term data are hard to come by, it's unclear whether Jenny Craig participants are able to keep the weight off over the long term, Hill says. Participants "lose weight [and] look great" but need to make lifestyle changes to keep the weight off down the line.
Description: An online, subscription-based service, eDiets was started in 1998. The program, which includes home delivery of balanced meals, snacks, and desserts, offers 20 diet plans (customizable based on foods you enjoy), and the website offers members-only access to menus, recipes, support groups, and diet experts.
Studies show: Adherence to the plan earned average marks from Consumer Reports, and weight loss was found to be below average. eDiets earned high marks in the magazine's nutrition analysis category.
Experts say: "The data that I've seen shows it really produces fairly minimal weight loss," Hill says. "But is that a bad thing if it takes little effort and you get a little bit of weight loss?"
Description: Based on the book Eat More, Weigh Less: Dr. Dean Ornish's Life Choice Program for Losing Weight Safely While Eating Abundantly by cardiologist Dean Ornish (Harper Paperbacks, 2000), the idea is that what you eat matters more than how much you eat. The book includes 250 low-fat recipes that, according to Ornish, can not only help you lose weight but also lower cholesterol and decrease the risk of heart disease and other illnesses. The caveat? Adopting this diet means no alcohol, fish, meat, oils, sugar, or white flour.
Studies show: Weight loss over the long term is average, according to Consumer Reports, but long-term adherence is below average. It also earned an average mark on the nutrition analysis scale.
Experts say: Hill says he likes the Ornish diet because it's low in fat. "But the problem is it's so low in fat that it's hard for people to stick with it," he says. "It's effective but maybe not practical." The plan also emphasizes physical activity, which is a "shortcoming of other diet plans," Hill says.
Description: This well-known high-protein, low-carb diet was first described in the book Dr. Atkins' Diet Revolution (Bantam, 1981). The diet is based on the concept that by eating fewer carb-containing foods and instead predominantly consuming protein plus vegetables with lots of fiber, your body burns fat rather than carbs as its main source of fuel. The first phase of the program mostly bans carbs, though later it gets a little less restrictive. (The New Atkins for a New You: The Ultimate Diet for Shedding Weight and Feeling Great (Fireside, March 2010), adds the latest information about the Atkins diet, such as a new requirement for at least five servings of high-fiber vegetables and advice about how to get rid of symptoms that may occur when switching to a low-carb diet.)