There's a new fad diet, and it comes from the land of stinky cheese and buttery pastries. The Dukan Diet has "taken France by storm," selling millions of books and gaining millions more followers over the past decade. Now the high-protein diet is making its American debut, with books hitting stores next month. Here's the skinny:

What is the Dukan Diet?
Created by a French doctor, Pierre Dukan, it's a high-protein, low-fat diet divided into four phases: attack, cruise, consolidation, and stabilization. In the first phase, dieters consume only non-fatty, high-protein foods, oat bran, and water. Weight drops quickly, by as much as 1 to 2 pounds a day. In phase two, dieters can add vegetables to their regimen. Phase three allows for two slices of cheese, a bit of fruit and cheese, two servings of carbs, and twice-weekly "celebration" meals with dessert and wine. In the fourth and final phase, dieters eat whatever they like six days a week, but on the seventh day return to "phase one" mode. This is to be done for the rest of one's life. Exercise requirements are light: Just 20 minutes a day of walking and a pledge to always take the stairs.

Does this really work?
Many French people think so. The diet has sold 3.5 million books in France, and reportedly helped 5 million of the country's citizens lose weight over the past 10 years.

Isn't it just a French version of the Atkins diet?
Dukan concedes he learned a lot from America's high-protein-diet guru, saying, "I have a lot of respect for Atkins." But he criticizes the Atkins diet for allowing unlimited fat consumption. "He was a legend in his time," he says, but now "Atkins is dead."

Does it have any celebrity supporters?
Model Gisele Bundchen and singer Jennifer Lopez, both new moms, reportedly lost their baby weight on the diet. The British press has reported that Carole Middleton, mother of Kate, has been using it to slim down for next month's royal wedding. And in France, "the diet has become so central to French culture that almost any public figure who has lost a lot of weight is labeled by the media as a Dukanniste," says Elaine Sciolino in The New York Times.

Is it safe?
Doctors aren't sure. "A once-daily multivitamin will not compensate for the nutritional goodness from fruits, whole grains, and healthy fats that are inadequate in the Dukan Diet," says Keri Gans, M.S., R.D., with the American Dietetic Association. The rapid weight loss and heavy restrictions also put dieters at risk for kidney problems, gallstones, and muscles loss.

Sources: New York Times, That's Fit, CBS News, Huffington Post, WebMD