Oct. 3, 2012 — “Drop 30 pounds in two months!”

We’ve all seen ads for miracle diets that promise to help us shed weight in days, weeks, or months.

But what happens next?

Do people stay the course and maintain the loss, or regain the weight with a vengeance?

A team of Israeli researchers followed participants for four years after an initial two-year workplace-based study to try and answer these questions. Participants followed one of three weight loss plans: a low-fat, low-calorie diet; a Mediterranean-style, low-calorie diet; or a low-carb eating plan without calorie restrictions. 

Overall, the Mediterranean diet led to the most dramatic changes, but people on the other diets also did pretty well. A Mediterranean diet is rich in fruits, vegetables, fish, whole grains, legumes, healthy fats like olive oil, and moderate amounts of alcohol. It is also low in sweets, meats, and saturated fats like butter.

Eighty-six percent of the participants were men, and most were considered moderately obese when the study began. Researchers also educated their spouses about the diet so changes could be made at home, too.

At two years, 85% of the participants were still following their diet programs. Participants on the Mediterranean diet and low-carb diet lost more weight than those on the low-fat diet.

Four years after the study officially ended, 67% of participants were still on their eating plan, 11% had switched to another a type of diet, and 22% were not dieting at all.

Mediterranean Diet Is the Winner

Everyone regained some of the weight they had lost in the original study, but all were thinner than when the study first began. The weight loss was highest in the Mediterranean and low-carb groups for the entire six-year period: about 7 pounds and close to 4 pounds, respectively. All participants also showed improvements in their total cholesterol levels.

“Our study suggests that the Mediterranean and low-carb diets have better [cholesterol] effects, as well as less weight regain,” says researcher Dan Schwarzfuchs, MD, of the Negev Nuclear Research Center in Dimona, Israel. “When a person needs to change their life habits, I try to tailor the diet to their personal preferences with precedence to Mediterranean or low-carb diets.”

Schwarzfuchs says the study has a “real life” aspect to it in both the weight lost and the health benefits. And even the fact that it took place in the workplace added a dimension to it: “When dealing with a change in lifestyle, the workplace is a great platform to generate a change, since we spend most of our waking hours at work.”

Importantly, after those two initial study years, there was no further support, and the employees were not committed in any way to the study.  “At four years follow-up, the intervention still has positive effects, especially in the Mediterranean and low-carbohydrate groups,” he says.

The findings are published in the New England Journal of Medicine.

Keeping It Off

“Most anyone can lose weight, but keeping it off is the harder part,” says Nancy Copperman, RD. She is the director of public health initiatives at the North Shore-Long Island Jewish Health System in Great Neck, N.Y.

“The Mediterranean diet seems to be the winner,” she says. “This is a livable diet and has positive physiologic benefits.”

But whether Mediterranean, low-carb, or another eating plan, choosing a diet that best fits with your lifestyle is a key to long-term success, Copperman says. It is more than just diet: “Getting regular physical activity also counts,” she says. “All in all, this is very impressive to me that so many participants kept going.”

Allison Krall, RD, is a dietitian from Ohio State University Wexner Medical Center in Columbus, Ohio. She reviewed the study for WebMD. “The Mediterranean diet won out overall. It is a more balanced diet with more options and choices,” she says. “Finding ways of eating that a person can stick to over the long haul is the key to losing weight and keeping it off because yo-yo dieting is dangerous.”

Preventive cardiologist Suzanne Steinbaum, DO, at Lenox Hill Hospital in New York City, is a big fan of the Mediterranean diet.

“Everyone can go on a diet and eventually they go off,” she says. “It is really about making healthy choices that you can live with over the long haul.”

Low-carb diets are restrictive and tend to be hard to stick to. “Choose a diet that is best for you, but is not too restrictive.” This is where the Mediterranean diet shines, she says. “It includes all food groups including whole grains and healthy carbs, so it is easier to stick with.”