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 July 14th, 2011

The Dukan Diet
by Dr. Pierre Dukan

The Dukan Diet, authored by French doctor Pierre Dukan, is one of the latest bestsellers among fad-diet books in the US, and it falls into the high-protein/low-carb approach.

It is not however one of the healthier choices in its genre. Unfortunately, the Dukan Diet is not only extreme in its protein regime, but also cuts out healthy fat sources along with carbohydrates. During its first (Attack) phase you eat only lean proteins, nonfat dairy, and eggs, supplemented with 1½ Tbl. of oat bran per day (no vegetables, grains, fruit, nuts or oils). During its second (Cruise) phase you get to add a selection of (low-carb) vegetables in every other day (still no grains, fruit, nuts or oils). According to Dr. Dukan’s numbers you would spend 2½ months in the Cruise phase to lose 25-pounds, or 4-months to lose 40-pounds. That’s in addition to the week you will probably have spent in the Attack phase.

Those results (around 2 pounds a week), however, are typical to ANY reduced-calorie-diet. So why exactly are you being advised to completely avoid so many healthy vegetables and fruits, etc.? There are three gimmicky reasons why:

Gimmick #1: maximize water-weight loss—providing the illusion of substantial early weight loss:
As I explain in Weight Loss Plateaus: How to reignite your weight loss, this is achieved simply by eliminating intake of carbohydrate containing foods. Dr. Dukan’s goal is to provide motivation, he explains, “Overweight people… need a fast-acting diet that brings immediate results, fast enough to strengthen and maintain their motivation.” No doubt he knows that more than half of what you appear to have lost on the scale will actually have been water. That’s why on page 72 he warns that “when vegetables are introduced the scale seems to get stuck and does not go down, or may even show a slight increase in pounds.” He further acknowledges, “eating only proteins has a powerful diuretic effect… a large quantity of water [is lost].”

Gimmick #2: Monotony of restricted eating (sensory-specific satiety): 
Dr. Dukan tells you outright, “The monotony of eating all proteins… has a marked effect on your appetite.” This is also why Dr. Dukan feels free to say (page 44), “eat as much as you want,” and (page 58), “eat as often as you like.” He knows that your choices are so severely limited that your boredom will ensure a low calorie intake!

Gimmick #3: "Calories Don’t Count": 
Fad-diet books always claim that “calories don’t count” because they all assert to understand a secret magical combination of “eating the right things in the right way” which they are revealing to you.  In this case it’s the shortlist of allowed foods on Dukan’s Attack, Cruise and Consolidation phases. The nonsensical assertion that “calories don’t count” is used as leverage to convince you to attempt to follow the nutty restrictions of the magical “eating the right things in the right way.” Apparently Dr. Dukan does know that calories do count however, which is why he warns you on page 37, “if you stray away from the list of permitted foods, you are no longer allowed to any quantity you like, and you will have to start counting how many calories you eat.” He knows that "straying" means not having the benefit of Gimmick #2, which will automatically result in higher calorie-intake.

The fact is that there are quality clinical trials published on every type of diet, and they all show no difference in weight loss between high-protein, high-carb, balanced diets, etc. Instead, despite what all the fad-diet gurus claim, the data confirm that weight loss still comes down to calories.[i],[ii],[iii]

If you make it through the Attack and Cruise phases of the Dukan Diet you can look forward to another 3- to 6-months in the Consolidation phase when you get to, "add 2 slices of bread, one fruit and cheese serving into your daily diet, along with 2 servings of carbohydrate and 2 "celebration meals a week." When you add it up someone losing 40-pounds would spend 8 or 9 months getting through phase three. Dukan suggests avoiding "dinner engagements" or "family celebrations" during the diet. So essentially he's suggesting you put your life on hold for three quarters of a year?

Dukan peppers the book with warnings, that if you don’t follow his guidelines exactly you will fail. Seriously though, has there ever been a dieter who didn't lapse? His warnings are basically a disclaimer essentially broadcasting, “don’t try to blame me when you start gaining your weight back!”

Here's the bottom line: focusing on protein, fat, or carbohydrates serves only to distract you from dealing with the real causes of overweight—too many calories and too little activity. The fad-diet gurus know you don’t want to hear that, and are all too eager to sell you their latest book. Your body weight however is a simple calorie-equation, and there’s just no fooling it.

Dr. Dukan did get something right when he said, "today we live in a land of plenty and our problem is not finding food, but refusing it."

If you want to lose weight, my best advise is to start where you are at, and look for "easy changes" to improve the quality of your diet. Cleaning the junk out of your cupboards and fridge wouldn't hurt! Forget "going-on-a-diet," instead approach it as a lifestyle change. Take it one day, and one meal, at a time. Start taking a walk every day. Understand that you choose your habits, but then your habits make you!

See Part II of this review here: Protein Mythology... get the Facts!


[i] Foster GD, et al. Weight and Metabolic Outcomes after 2 years on a Low-CHO versus Low-fat diet. Ann Intern Med 2010;153(3):147-157

[ii] Foster GD, et al. A Randomized Trial of a Low-Carbohydrate Diet for Obesity. NEJM 2003;348:2082-90.

[iii] Skov AR, et al. Randomized trial on protein vs. carbohydrate in ad libitum fat reduced diet for the treatment of obesity. Int J Obesity 1999;23:528-36.