One of the latest diet crazes is the Dukan diet. According to the tabloids and blogs, Kate Middleton went on it before her marriage to Prince William in 2011 and dropped two dress sizes. Developed by Dr. Pierre Dukan, a French neurologist-turned-nutritionist, the diet has been published in best-selling books across Europe and now in the U.S.
Not surprisingly, the Dukan diet website features lots of glowing testimonials. But not everyone agrees it’s the best diet du jour.
"Attacking” the weight
The Dukan diet is yet another high-protein/low-carbohydrate eating plan that promises rapid and permanent weight loss. It has four phases, all of which include high-protein foods, oat bran, lots of water and a little exercise. In the “Attack” phase, you eat unlimited amounts of lean high-protein foods, with no carbs at all. In the “Cruise” phase, you choose from a list of nonstarchy vegetables (such as spinach and green beans) on alternating days.
In the “Consolidation” phase, you eat vegetables every day and gradually reintroduce small amounts of forbidden foods, including fruits, cheese and whole-grain bread; every week you can also have two “celebration” meals and one or two servings of starchy foods, like pasta, polenta or beans. In the “Stabilization” (maintenance) phase, you can eat anything you want—as long as you include a protein-only day once a week, eat 3 tablespoons of oat bran a day, walk 20 minutes daily and always take the stairs instead of the elevator.
The French Atkins?
The Dukan diet differs from Atkins because there’s no carb counting and, in later phases, you can eat unlimited amounts of most vegetables. The Atkins diet is more restrictive about vegetables. Dukan also emphasizes lean protein, while Atkins allows unlimited fat from unhealthy sources, such as hamburgers, bacon and ice cream, with no need to trim fat from meat or skin from poultry. And where Atkins promotes its protein bars and shakes, Dukan recommends unprocessed whole foods.
That’s not to say there aren’t sales-promoting pitches—for one, Dukan Diet brand oat bran and other foods and supplements are sold on the website. And the diet comes with a questionable fee-based online coaching program.
Duck the Dukan
It’s not surprising that people lose weight on this diet—after all, cutting down on carbs cuts out lots of calories. The high protein, along with the fiber from oat bran, may also make you feel more full so you may eat less.
But as with all low-carb diets, most of the initial loss will be body water, not body fat. And as with other fad diets that restrict entire food groups, you’ll miss out on important nutrients, phytochemicals and other compounds that only those foods provide. Taking a multivitamin/mineral supplement, as the diet recommends, won’t make up for all of them. If you stay too long in the most restrictive first phase, you could especially end up with significant nutrient deficiencies.
The bigger question is whether the weight stays off. According to an independent French survey of close to 5,000 Dukan dieters, published in 2011 in the journal Obésité, about 35 percent had regained the weight they lost within a year, 64 percent after two years and nearly 80 percent after four years. That is, the diet seems to be no more effective than other restrictive fad diets over the long term.
Be aware, too, that high-protein diets can put added stress on the kidneys. People with diabetes or kidney disease should not be on them—and many older people are unaware that they have impaired kidney function. Pregnant and breastfeeding women should also avoid high-protein diets. Side effects of the diet include dry mouth, bad breath, fatigue and constipation.
The Dukan diet is unbalanced and potentially risky, according to a French health agency. In 2011 the British Dietetic Association named it one of the worst fad diets, calling it “confusing,” “very rigid” and not backed by science.
Bottom line: Like other diets, the Dukan diet may help you lose weight initially. But the real challenge is keeping it off—and there’s no evidence that it leads to lasting weight loss. Plus, its rules can be hard to follow, and the diet itself hard to swallow. As we’ve said many times, different diets work for different people and the key is to find a balanced reduced-calorie eating plan that you can stick to for the long haul, whether it is higher in protein, carbs or healthy fats.