Which Diet Is Right for You?

Here's the skinny on six top diets to help you achieve weight loss success.

Medically Reviewed by Michael W. Smith, MD on May 21, 2009
Written by Stephanie Watson
9 min read

These days there are dozens of diet and weight-loss programs available and you may have tried a good number of them. This summer you may even be determined to truly and finally diet and ditch those pesky extra pounds. But where to begin? Googling the word "diet" brings up more than 29 million hits, and it’s often hard to tell the science from the latest celebrity fad. To help get those pounds off for bikini season, WebMD the Magazine scrutinized seven of the most popular diets to help you narrow down the one that’s best for you.

The basic idea behind these low-carb diets is that by cutting carbohydrates, you force your body to start digging into stored fat for energy (a process called “ketosis”). Low-carb diets ramp up the amount of daily protein you eat, so you feel satisfied on fewer calories.

Research shows you can lose weight on a low-carb diet, but not always in the healthiest way. In the first phase (the "induction phase") of the Atkins Diet, you’re directed to cut down to just 20 grams of carbs a day (the average American eats about 300 grams a day), while you beef up on protein. Our experts say this kind of extreme carb-cutting isn’t sustainable, and it won’t give you as many fruits, vegetables, and whole grains as you need.

Some people see the protein-heavy first phase of the Atkins Diet as carte blanche to pour whole cream in their coffee and down double cheeseburgers like there’s no tomorrow. "The issue here is you don’t discriminate between heart-healthy fat and artery-clogging fat," says Madelyn Fernstrom, PhD, CNS, founding director of the University of Pittsburgh Medical Center’s Weight Management Center.

Later phases of the Atkins Diet are less restrictive and more sustainable, and you can tweak the diet to make it healthier by choosing lower-fat protein sources, such as egg whites, Canadian bacon, and skim milk, Fernstrom says.

The South Beach Diet also is divided into phases. Though its first two-week phase is similarly carb-restrictive, later phases start to incorporate more "good" carbs, such as whole-grain breads and pastas. The emphasis throughout the diet is on healthy sources of protein (lean meats, reduced-fat cheeses, low-fat dairy) and fats (nuts and fish) to create a lifestyle approach you can maintain over the long term.

Overall, our experts say, it’s a more well-rounded way to go. "South Beach is a wonderful approach for people because it is a heart-healthy Atkins," Fernstrom says.

Bottom line? Low-carb diets work for weight loss, but skip the induction phase. Don’t cut carbs below 100 grams per day, and avoid saturated fats.

Although Weight Watchers has evolved over the years, its core message is the same: Live a healthy lifestyle and you’ll lose weight. You can eat whatever you want, but each food is assigned points, and you’re limited to a certain number of points each day, based on your weight.

For example, if you weigh 180 pounds, you can eat between 22 and 27 points a day. Points are calculated based on the fat, calories, and fiber in each type of food. Eat an English muffin, and you’ve used up just two points. A large slice of veggie pizza will set you back six points.

Essentially Weight Watchers is nothing more than your basic low-fat diet, meaning lots of low-fat protein, whole grains, and fruits and vegetables, but it does offer one benefit.

"To me the big advantage of Weight Watchers is the social support network," says Donald K. Layman, PhD, professor emeritus of nutrition in the Department of Food Science and Human Nutrition at the University of Illinois at Urbana-Champaign. During group meetings members share their successes and encourage one another.

But the meetings can be a detriment if you have a demanding schedule, says Fernstrom, although you can choose to do Weight Watchers completely online. Another downside to Weight Watchers: Points don’t discriminate. It’s up to you to decide between the scoop of ice cream and baked chicken breast with four points each.

Bottom line? Weight Watchers is a healthy long-term plan if you can stick with it and watch your calories. If you don’t like counting points, the diet also offers a more flexible point-free plan, which eliminates the counting and instead focuses on foods that fill you up quickly (such as brown rice, lean meats, and avocados).

The Volumetrics plan, created by nutritionist Barbara Rolls, PhD, is based on the idea that people get hungry, and when they’re hungry they want to eat. Volumetrics aims to satisfy that hunger, but instead of filling up on energy-dense foods such as crackers and cookies, which pack a lot of calories for their size, you load up on foods with a low energy density, like vegetables and soup, which are high in fiber and water and low in calories. Then you can eat healthy low-fat meals without feeling deprived.

Fernstrom says the idea of the Volumetrics diet is rooted in good science. "It’s based on 25 years of scientific evidence showing that people will eat less, for example, if they have a big salad or bowl of tomato soup. The way you fill up is by having foods that are high in fiber and high in water," she says. "It’s certainly reasonable, and it’s the fundamentals of a diet plan for life."

Layman isn’t as convinced. "[Rolls has] found that if you eat things that have a high fluid volume ahead of a meal … you will consume fewer calories. I think that’s perfectly good research, but I’m not sure that everybody, at every meal, can have soup ahead of it," he says. He views Volumetrics as a component of a diet, rather than a lifestyle.

Also, because the Volumetrics diet relies heavily on homemade soups, casseroles, and stews, you have to be extra vigilant about meal ingredients if you’re leading a busy lifestyle and depend on convenience and restaurant foods. You might want to consider canned soups, especially the low-calorie and low-sodium varieties on market shelves.

Bottom line? Volumetrics is a sensible, low-fat diet. It can work for people who get filled up on soups, salads, and vegetables, but those who don’t feel satisfied after a plate of greens may stay hungry enough to veer way from the plan.

Jenny Craig takes the thinking out of dieting. The plan provides you with three meals plus snacks every day, and you supplement them with your own fresh fruits, vegetables, and low-fat dairy products. You can either pick up your food at a local center or have it shipped directly to your home every two to four weeks.

For the most part, Jenny Craig is based on the government's Food Guide Pyramid. You can eat a variety of foods (even chocolate), but everything is low-fat and portion-controlled.

Cutting down your portions will help you trim down, but Jenny Craig isn’t a long-term weight-loss solution, says Thomas Halton, DSc, licensed nutritionist and owner of Fitness Plus, a nutrition counseling service in Boston, Mass. "The concern is: Will it really teach you how to eat right? Are you going to eat that for the rest of your life?" Layman agrees. "If you don’t learn new behaviors in the first six months of going on a new nutrition program, then you’re going to fail at it and a year later you’ll be back as heavy as you were, if not heavier."

What Jenny Craig does offer is an important lesson in portion sizes, Fernstrom says. "I tell people to keep the containers from their packaged meal plan so they can use them for their own food."

Bottom line? Jenny Craig is healthy and takes the guesswork out of dieting, but the food gets pricey ($120–$145 a week, plus shipping and handling costs if you’re having it sent to your home), and a lot of people eventually want to get back to eating food that doesn’t come from a plastic container.

Cardiologist Dean Ornish, MD, originally designed his very low-fat diet to help people with heart disease lose weight and lower their cholesterol levels. In his research, his diet did trim people down and it protected against heart disease, although it wasn’t clear whether the diet alone -- or the added exercise and other lifestyle interventions -- made the difference.

Eat More, Weigh Less is his recent approach -- slightly less militaristic than the very low-fat vegan regimen used in many of his studies, although still pretty restrictive. His goal is to change the average American diet from its current composition of 40% fat, 20% protein, and 40% carbs to 10% fat, 20% protein, and 70% carbs.

The bulk of the diet is made up of fiber-rich whole grains, fruits, and vegetables. Meats are severely limited, and simple carbs (read: sugar) are forbidden. Because fat has almost twice the calories of carbohydrates or protein, Ornish says changing the math allows you to eat almost a third more food without increasing calories.

The diet is also supposed to prevent you from feeling deprived, but our experts disagree. "He has 10% of calories as fat -- you’re going to be starving on that," says Halton. "My feeling with the Ornish diet is it’s too extreme. It’s just too low-fat and too low-protein," says Layman. "Fat gives the diet texture and flavor. If you get too low, it’s just too hard to sustain."

However, if you’ve already trimmed most of the fat from your diet and are looking for an extra weight-loss boost, Fernstrom says the Ornish diet can work as a good second step.

Bottom line? Eat More, Weigh Less is probably too restrictive for most people to stick with, but if you can handle the hunger, your heart will probably thank you.

Nutrition expert Connie Guttersen, RD, PhD, designed the Sonoma Diet for people who love to eat. She calls it “the most flavorful weight-loss plan under the sun,” and with dishes such as pork chops with rosemary, Greek pizza with feta cheese, apple-blueberry tart, and – yes -- even red wine on the menu, it’s hard to argue.

Sonoma is just one version of the Mediterranean style of eating, which favors fresh fruits and vegetables, whole grains, fish, nuts, and olive oil. Halton says it’s a good, balanced approach. “I think it’s a wonderful diet," he says. "It takes the nice aspects of a lower-fat diet -- not eating saturated fat and cholesterol -- but also takes the benefits of a lower-carb diet, where you’re not eating refined grains."

As an added bonus, there’s some evidence a Mediterranean-style diet can lower your risk of diabetes and heart disease, and might even prolong your life.

Fernstrom likes the Sonoma Diet’s "cool name," but says there’s really nothing special about it. "It’s just a twist on a moderate diet." The food is delicious, but it might be too much of a good thing, she adds.

"It shouldn’t taste too good because people are going to have trouble having a small amount," she says. "You do want to enjoy food, but you still have to moderate the portions."

To help you, the diet offers a portion guide that limits your servings to a 7-inch plate or 2-cup bowl for breakfast, and a 9-inch plate for dinner. It also tells you how to fill those plates.

Bottom line? The Sonoma Diet is tasty and good for your heart, but watch the fat (olive oil and nuts are "good fats," but they’re still fats) and portion sizes.

No matter which diet you're considering, watch for these warning signs that what seems like a perfect program won't work.

Quick weight loss. "Anything that promises more than three pounds in a week should be avoided," according to nutrition professor Donald K. Layman, PhD.

Diet gurus. "People think just because a doctor wrote a book, it's expert advice," says Layman. "Check to see if the author has studied nutrition at a very high level."

Where did the carbs go? "Anything that excludes whole food groups -- anything that says 'five magic weight-loss foods' -- simply isn’t true," explains nutrition expert Madelyn Fernstrom, PhD, CNS. No carbs, ever? No dice.

No long-term plan. "If you can’t see yourself on this diet six months or a year from now, you shouldn’t start it," Layman says.