Kate Middleton, the Duchess of Cambridge, arrives at Westminster Abbey. (Ben Stansall / AFP / Getty…)
When Catherine Middleton walked down the aisle of Westminster Abbey on Friday — a willowy vision in white — she appeared noticeably thinner than she had in previous months.
Her weight loss sparked rumors that she was on the Dukan diet — what appears to be a French spin on the high-protein Atkins diet — after Middleton's mother, Carole, acknowledged using the plan to shed pre-wedding pounds.
Suddenly, the diet that sold 4 million copies in France was making headlines in the States, with its promise of instant weight loss without hunger, portion control or counting calories.
Photos: Royal Wedding
The diet's author, Dr. Pierre Dukan, a French family practitioner, is capitalizing on the sudden surge in media exposure to promote his mission (attack the obesity problem in the U.S.) and the American version of his book. "The Dukan Diet" hit bookstores in late April with a cover stating, "The Real Reason the French Stay Thin."
Many nutritionists and other health experts dismiss the eating regimen. They say it's just another fad diet that, while impressive in its immediate results, could be risky over the long-term.
"It just doesn't make sense based on the science we know," said Joan Salge Blake, a clinical associate professor at Boston University and spokeswoman for the American Dietetic Assn. "When you eliminate major food groups, you have the potential to eliminate major nutrients."
The diet can indeed have less-than-glamorous side effects, such as constipation, dry mouth, bad breath and fatigue because of its lack of carbs, fruit and vegetables. Even Dukan acknowledges this.
However, some obesity experts say that high-protein diets such as Dukan's may be better than traditional calorie-lowering plans — at least initially — at curbing hunger pangs and providing a more rapid drop on the scale.
"Diets high in protein tend to be associated with a little higher [initial] weight loss," said Robert Eckel, a professor of medicine at the University of Colorado and past president of the American Heart Assn. Over longer periods, such as a year or two, he said, the results achieved via these regimens tend to rival more traditional calorie-restriction plans.
How does it work?
The Dukan diet is divided into four phases — two for weight loss and two for reintegrating foods and maintaining weight loss.
The first and most difficult step is the "Attack Phase." This level lasts from two days to a week, depending on the amount of weight loss sought, and requires dieters to eat only protein — such as lean cuts of beef; fish and shellfish; eggs; and nonfat dairy products — to jump-start weight loss. It allows a minimal amount of oat bran in one small galette, or pancake, each day, and mandates a daily 20-minute walk.
The second, or "Cruise," phase alternates between days of protein and days of protein and nonstarchy vegetables until the desired weight is reached. Fruit and carbohydrates are verboten.
The third, or "Consolidation," phase slowly reintroduces some carbohydrates, fruit and cheese, and allows two "celebration" meals a week that can include a glass of wine. It lasts five days per pound of weight lost.
Last comes "Permanent Stabilization." This phase requires participants to make a lifelong commitment to taking the stairs rather than the elevator, eating three tablespoons of oat bran a day and picking one day per week to eat only proteins in exchange for eating most anything the other days of the week.
The diet may sound similar to the Atkins diet launched in the 1970s, but it relies on low-fat protein and eschews Atkins staples such as bacon and butter.
"For me, fat is enemy No. 2" behind carbohydrates, Dukan said in a phone interview with The Times. Moreover, he said, his diet doesn't require participants to count their carbs and it helps keeps the weight off long-term via the stabilization phase.
"It's very simple and very structured," he said.
Food experts complain that the diet doesn't teach overweight people how to eat a moderate balanced diet. Many obesity and health researchers contend that a more well-rounded eating plan is key to disease prevention and longevity.
France's own government food agency has identified the Dukan plan as one of 15 "imbalanced and potentially risky diets," because of its restriction of food groups and the nutrients they provide.
The British Dietetic Assn. branded Dukan one of the "five worst diets of 2011."
"Sadly there is no magic wand that you can wave," said Sian Porter, a dietitian and spokeswoman for the British group. "It may be obvious, but if you want to lose weight, you need to eat a nutritionally balanced and varied diet with appropriately sized portions and burn off more calories than you consume."