A really dumb diet from France

After experiencing so many years of ridicule (now effectively past history) with the Zone diet, I never thought I would possibly criticize another new diet unless it was either dangerous or just plain foolish. The newest diet from France is both.

Called the Dukan diet, this program is a strange combination of the Atkins diet with a French twist. As usual, there are number of diet phases that have to be followed. The first one is downright dangerous as it recommends unlimited amounts of lean protein, 1½ tablespoons of oat bran and lots of water. The reason this phase is dangerous is because there are virtually no carbohydrates or fats to counterbalance the protein. My best estimate is in this first phase more than 90 percent of the total calories are coming from protein. This will overwhelm the liver's capacity to metabolize the excess protein leading to a condition known as “rabbit starvation” (1). This was a condition experienced by early Arctic explorers who only subsisted on lean protein. They quickly became dehydrated as the body desperately tried to excrete excess ammonia (the first breakdown product of protein) through the urine that could not be converted to urea by the liver. This leads to dehydration, diarrhea, nausea, low blood pressure and fatigue. At least on the Atkins diet there was a lot of fat coupled with the protein to help the liver metabolize the ammonia from the protein into urea that could be easily removed in the urine.

The dehydration from such a severely ketogenic diet explains the need for lots of water. As far as the oat bran, it contains virtually no carbohydrate, but lots of soluble fiber to help expand the stomach. Yes you will lose weight (primarily water) and insulin levels in the blood will drop dramatically, but you will reduce the elasticity of the blood vessels (2) and increase insulin resistance in the liver (3). The decrease in the elasticity of blood vessels increases the likelihood of a heart attack, (4) and the growing insulin resistance sets the stage for liver dysfunction that always promotes weight regain. This first phase is called the Attack Phase, I assume because it attacks your liver and your metabolism.

Phase 2 of this diet is just as wacky. Now you increase the oat bran to 2 tablespoons per day and have some vegetables every other day. This phase remains a highly ketogenic diet, meaning the liver and blood vessels are still in a metabolic mess. This is called the Cruise Phase. I guess this means you are cruising for a hard landing even though you are still losing weight.

If you last through the first two phases (about two months), you enter into the Consolidation Phase that is just as wacky as the Cruise Phase, but in the other direction. Now you can add non-starchy vegetables every day and a piece of fruit (I applaud these additions). But then why does this diet let the person start eating bread every day and rice and pasta twice a week plus two Porky Pig meals including dessert and wine (that's the French twist). It's like an insidious plot to demonstrate how quickly you will regain the lost weight, but now as newly synthesized fat. Of course, by following this Consolidation Phase, it is virtually guaranteed you will consolidate the lost weight into new stored fat.

Finally, there is the Stabilization Phase where you can eat anything you want (mac and cheese, fried chicken, etc.) as long as you eat only lean protein one day each week. Fat chance you will ever get there.

You probably won't die on the Dukan diet, but you will mess up your liver metabolism making it much more difficult to lose the resulting regain of fat mass on the Consolidation Phase.

I am frankly getting a cold sweat as I write this blog since I am sounding a lot like Dean Ornish yelling at Bob Atkins in the old days. But even Bob would say the Dukan diet is just plain stupid.


  1. Silsborough S and Mann N. “A review of issues of dietary protein intake in humans.” Int J Sports Nutr Exerc Metab 16: 129-152 (2006)
  2. Buscemi S, Verga S, Tranchina MR, Cottone S, and Cerasola G. “Effects of hypocaloric very-low-carbohydrate diet vs. Mediterranean diet on endothelial function in obese women.” Eur J Clin Invest 39: 339-347 (2009)
  3. Jornayvaz FR, Jurczak MJ, Lee HY, Birkenfeld AL, Frederick DW, Zhang D; Zhang XM, Samuel VT, and Shulman GI. “A high-fat, ketogenic diet causes hepatic insulin resistance in mice, despite increasing energy expenditure and preventing weight gain.” Am J Physiol Endocrinol Metab 299: E808-815 (2010)
  4. Yeboah J, Crouse JR, Hsu FC, Burke GL, and Herrington DM. “Brachial flow-mediated dilation predicts incident cardiovascular events in older adults.” J Am Coll Cardio 51: 997-1002 (2008)

Nothing contained in this blog is intended to be instructional for medial diagnosis or treatment. If you have a medical concern or issue, please consult your personal physician immediately.

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This entry was posted in Zone Diet and tagged , by Dr. Barry Sears. Bookmark the permalink.

About Dr. Barry Sears

Dr. Barry Sears is a leading authority on the impact of the diet on hormonal response, genetic expression, and inflammation. A former research scientist at the Boston University School of Medicine and the Massachusetts Institute of Technology, Dr. Sears has dedicated his research efforts over the past 30 years to the study of lipids. He has published more than 30 scientific articles and holds 13 U.S. patents in the areas of intravenous drug delivery systems and hormonal regulation for the treatment of cardiovascular disease. He has also written 13 books, including the New York Times #1 best-seller "The Zone". These books have sold more than 5 million copies in the U.S. and have been translated into 22 different languages.

39 thoughts on “A really dumb diet from France

  1. I’ve heard of it. It’s the diet princess-to-be Kate Middleton is following before her wedding. That’s the danger, when a celebrity sponsors a diet like this, everyone follows suit.

  2. Thank you so much for clarifying that and the phases of low carb diets. I did the rage Bernstein diet here ( severe caloric restiction and low carb)in Canada and gained all of the 40 pounds back. What I worry about is the damage that ketosis does to bone and other organs in persons over 45. I am guessing that younger participants in that diet can bounce back more readily but I was 50 at the time and my teeth demineralized and my hair fell out. They don’t tell you that in the expensive consult. Even thought it is medically monitored, who would know that decreased vessel elasticity is not causing heart attacks in that age group- I was lucky I guess. Oh they do prescribe slow K and a multitude plus administer sub cutaneous b vitamins as they “speed up fat loss”. Oh, herenis the ethical part: if you choose to stop their program because you wish to or in my case the monitoring doctor stopped me, they will and did deny me access to the “maintenance program” because I did not reach the foal that I arbitrarily set. Please review this rage diet for Canadians, Dr. sears. Bobbi

    • I went to his web site and found very little information other than locations of his clinics. This is usually not a good sign. The fact that it is medically supervised indicates that their may consider risk in following such a dietary program for even a short time.

      I am afraid your experience is similar to the experience many others have had with such diets.

  3. I live in London and I can confirm that the Dukan diet has been ubiquitous in the newspapers and magazine supplements, and I imagine, the women’s magazines as well. Kate Middleton is part of the reason, although she’s not (yet) royalty. (For really stupid royals, follow the antics of Prince Andrew.) When I first read about the Dukan diet a week ago, my reaction was “Dr Sears will blow a gasket” and that prediction proved correct! I lived in Paris for 3 years as well, and based on the high protein foods I found in the French pharmacies, the women there just love extremely precisely-specified diets. And the great thing about the Dukan diet is that you can go back to bread, wine and profiterolles — otherwise, quelle misere!!

  4. I am french and a LOT of people follow this diet here, I don’t know why. The deprivation of all food except lean protein is just unbearable to me from a psychological point of view, besides it makes you sick, and ready to gain weight very fast if you stop the diet. To my opinion this is just stupid. Dukan says in his book that “fat people” are not able to follow a proper diet with various food types, I totally disagree. I had food disorder but I got rid of it ten years ago and I no longer have problems with food. We have wonderful food products here, meat, fish, fruits, veggies, cheese, why our relationship with food is so problematic ? Why women substitute their meals with disgusting protein powder to lose weight, all of that without doing any exercise ? I really do not understand.

    • I agree with your comments. Fat loss takes time and only requires an appropriate adjustment of the balance of lean protein and vegetables and fruits. It is usually time compression that is the problem.

  5. Dr. Sears,
    You specifically chose to pick this Dukan diet plan from France to criticize but you say nothing about another diet plan from France by Michael Montignac, who pioneered the glycemic index and sold millions of copies of his diet concentrating on the glycemic index way back in the 1980′s.
    At the end of 1987, Montignac published his famous book Eat Yourself Slim… and Stay Slim! a layman’s version of the Montignac Method. This book is such a great success that it is sold in 40 countries and has broken all sales records in its field with over 16 million copies sold by the end of 2004. You didn’t publish your first book ‘Enter the Zone’ until 1995.
    Please, give credit to where credit is due.

    • Montignac discussed the glycemic index first discussed by David Jenkins in 1981, whose work is thoughly mentioned in many books. No where in any of Montignac books (I think he only wrote one) did he discuss the need for balancing the glycemic index (and really the glycemic load) at every meal with an necessary amount of protein to balance insulin and glucagon responses. Furthermore, he never discussed the role of excess insulin in the generation of inflammatory eicosanoids by increasing the production of arachidonic acid. If you can find such references on arachidonic acid, eicosanoids, inflammation and the role of inflammation in chronic disease in his book, please let me know.

  6. I used to follow that diet. It is quite popular in my country and many women have lost a lot of weight and some of them didn’t regain it. I could’t really follow it – I love fruit and veggies and excluding them from my diet was so hard. I lost some weight but I spend the summer in the USA and I gained it all back and I even put on some more.
    The thing that made me try it at first place was that I could eat as much as I wanted and I could loose weight quickly.
    I guess it was really foolish. How bad could the damage on my metabolism be? I just started the Zone diet a few days ago and I love it. Will this diet repair the damage from the Dukan diet? I really hope I will be able to loose the extra weight I gained and finally keep it – so far I keep yo-yo dieting.

    • The damage generated by any unbalanced diet will be increased inflammation. The Zone diet is a dietary program designed to reduce cellular inflammation and in maintain it under control for a lifetime.

      The weight regain is caused by increased cellular inflammation generated by returning to old dietary habits. Once you establish new ones and maintain them, then you have a dietary pathway to long-term wellness that includes weight maintenance.

  7. Dear Dr. Sears,
    This is not a comment to your article. But it has to do with that I bought some of your bread products! I selected three products that did not have FRUCTOSE and SUCRALOSE in it. When I received the bread, I examined the nutrition label and discovered that all three products had SUCRALOSE in them. The SUCRALOSE was NOT listed under the ingredients on your web site where you sell the bread.
    My question is: Can you possibly leave out the SUCRALOSE in the bread, bagel and bun products? Also I’d be thrilled to buy some of your cookies etc. if they did NOT have FRUCTOSE and

    • Until we established a new water system with very tight pH control, we had to add vingear to the bread to control bacterial growth (bread doesn’t last forever). We used the sucralose to cover the taste of the vinegar. Our new bread products are made with the improved water purification that allows us to take out much of the vinegar and thus the sucralose. The new labels being prepared reflect this as does the web site.

      70% of the carbohydrates in fruits is fructose and 30% of the carbohydrates in vegetables is fructose. The clinical data is quite clear that consuming less than 60 grams of fructose per day has absolutely no adverse effects on human physiology.
      That’s why I don’t recommend eating more than 200 Zone cookies per day.

  8. Continuation: Also I’d be thrilled to buy some of your cookies etc. if they did NOT have FRUCTOSE and SUCRALOSE IN THE PRODUCTS.
    According to Dr. Jonathan V. Wright, WA state:

    “Although some natural food stores still sell bags of pure fructose, most know to caution their customers against it. Put simply, once fructose is separated from whole fruit or other sources, it’s just another one of those “refined carbohydrates” we should avoid completely.”

    Please advice!

    • Dr. Wright knows better than that. It is not fructose, but the amount of fructose. Under 60 grams of fructose per day has no adverse effects on humans.

      To take that argument to it extreme, you should never eat fruits and vegetables because they also contain fructose. Only grains and starches contain no fructose.

      • With all due respect Dr. Sears, I must protest your response to fructose.
        Fructose in fruit and vegetables digest very slowly so that there is a minimum amount of sugar spike. Refined fructose will cause a sugar spike that isn’t so hard to figure.

        • Refined fructose does not cause a glucose spike. It’s glycemic response is about 20% that of glucose Many fruits have a much higher glycemic response that refined fructose. However, the benefits to fruits and vegetables is that they contain polyphenols, which are far more important as anti-inflammatory agents that the slower glycemic response which modulates insulin secretion.

  9. According to DeGrey’s book, “Ending Aging”, page 173, people who followed the Atkins Diet for a month suffered a doubling of their methylglyoxal levels, which is ‘up to 40,000 times more reactive’ than sugar, in the oxidative sense, and ‘known to cause wide-ranging damage in the body’. Makes me wonder how bad this Dukan diet would be, oxidatively speaking.

    • Medifast has been around for more than 30 years. Initially is was a medically supervised fast under 800 calories. Now it has been retooled as a low calorie diet.

      The slumping price of its stock probably indicates that they don’t have too many repeat customers.

  10. Dr Sears, I have had great success with the Dukan way of eating. I don’t get on here to argue diet vs diet, but to ask that you go back and see that the diet has plenty of carbohydrates. All phases of the diet allow as much fat free dairy as desired, and we all know that milk has sugars along with protein. I consider it to be a very balanced diet once you reach the Cruise phase and add in the low glycemic index vegetables, and the Attack phase only lasts a few days. Not long enough to damage your liver. Coupled with the mandatory 20 minute walk per day, the diet is very satisfying and easy to follow. After being on the diet for 3 months, I had the best lab results I have had in years, specifically glucose, cholesterol and triglycerides.
    The Zone diet is a good diet, too, but not everyone can eat fruit without their blood sugar spiking. Dukan keeps my blood sugar stable.

    • The best diet is the one that works for your biochemistry and genetics. Unfortunately every one is different genetically. I usually recommend on the Zone diet for females not to eat more than one serving of fruit per day and for males not to eat more than two servings of fruit per day. The vast majority of the carbohydrates such come from vegetables, with only minor components coming from grains and starches.

  11. I make my own breads and pizza dough and cakes and cookies and cinnamon buns (my favorite – especially yummy) very cheaply using light tasting olive oil and no salt and stevia sweetener and a special high protein ‘carbalose flour’ (no soy) that has 90% less carbohydrates than ordinary flour and the lowest glycemic index and glycemic load than any other flour.

      Would you please care to share your hi-protein bread dough recipe? Do you actually make cookies, buns of the same hi-protein bread dough? I haven’t been able to find an effective hi-protein bread recipe online.
      Email: lise.k.p@gmail.com

  12. Not arguing your point about the Dukan Diet but it might be better if you had not criticized it yourself as it just seems that you would have a conflict of interest. If it’s successful, it’s a threat to your market share so you are invested in its failure. Regardless if that is true or not you can see how someone might think that and it would discredit your argument.

    • Simply my opinion. That’s why diets have to analyzed in clinical experiments. To date a great number have been published on the Zone diet and none on the Dukan diet. One of my publications in the American Journal of Clinical Nutrition compared the Zone diet to the Atkins diet under highly controlled clinical conditions. That study demonstrated that Zone diet reduced cellular inflammation and the Atkins diet increased cellular inflammation.

  13. I’m from Spain where the Dukan Diet is also a bestseller. I thank you Doctor for your comments and sincerity, and I absolutly don’t agree with Robyn!. From my point of view please always let us know what you really think on other diets!.
    One recommendation: you need more marketing on your diet in Spain!. And it’s a shame we don’t get to have here all the products that you offer in the US!!!. For when????.
    I ‘ve been doing for the past 2 months a ketogenic diet….without really studying the medical side of it….or down side really. Thanks to my doctor I’m now doing the Zone and eating healthy.
    I need to ask you a question on the minimum portions (in Spain we call them Bloques, not sure how you call then in english). If I use the method of calculation from the book, I need 8 portions a day. But according to the website calculations in Spain, http://www.enerzona.net, I get 11 portions. The question is, is 8 portions too low???. My Doctor has advised me to eat 8 portions but some experienced people doing the zone diet advise me that that is a too low intake.
    Please advise and thank you very much!

    • One block (or bloques) is approximately 100 calories. I like to have 11 blocks as a minimum per day. That would be three meals each of at least 3 blocks each and two one block snacks. The typical female will need 11 blocks per day and the average male 14 blocks per day. Here lies the Zone Paradox which is that if each of your Zone meals and Zone snacks are balanced with protein, carbohydrate, and fat, you will have no hunger because of improved hormonal control in spite of the low calorie content.

  14. Pingback: Dukan Diet: Does It Work?

  15. Pardon d’ écrire en français ! J’ espère que vous pourrez traduire .
    Le régime DUKAN est en France une folie ! Livres , articles dans les journaux , interviews ….
    Je suis heureuse de pouvoir vous remercier , Dr. SEARS , car depuis 16 ans je suis votre méthode ( connue grâce au livre “Le juste milieu dans votre assiette ” ) et je suis en bien meilleure santé qu’ avant . Au sujet du poids , j’ ai perdu 28kgs ( et donc fait baisser mon diabète ) , je n’ ai presque plus de douleurs dues aux rhumatismes , plus d’ aphtes , la fatigue , qui était continuelle avant , ne survient qu’ après le travail !
    Je mange chaque jour selon vos principes , c’ est devenu une habitude , par contre , je ne peux pas résister , parfois , aux fromages !!!!
    MERCI pour tout !!!

  16. So basically you are dissing someone else’s diet plan to promote your own…. That’s a little shallow and unethical don’t you think?? I’ve been following the Dukan Diet since May – I lost 2 stone in 3 months and have been successfully following the Consolodation diet since August. I haven’t gained a pound.. and to top it off, my blood pressure and heart rate have dropped therefore significantly reducing my risk of cardiovascular disease. Recent blood tests have come back normal and I have more confidence in my physical appearance than ever before. I think that the only reason that you have to so violently attack another diet plan is because yours isn’t as effective. Different diet plans work for different people… so try another approach Dr Sears as bringing down a diet plan that has worked for millions of people in order to try and promote your own is despicable…. and certainly won’t be convincing me to try it… not that I need to, seeing as the Dukan Diet works so well!!

  17. I had my annual labs drawn after the fifth day of Dukan attack. (I know it was a bad time but had to get them done before the end of the year for insurance purposes) My bilirubin was 2.6. Nothing else was abnormal except BUN was 26. I’ve never had these labs elevated before. Dr. Sears, do you think this could be from eating all lean protein for five days? I never drank the recommended amount of water. I felt fine though. I’m worried about that bilirubin. I was retested today to get a fractionated bilirubin. Waiting for the result, nervously. I’m 59. The good thing was my HDL was 81. I’ve always eaten low carb for a number of years but never did anything this extreme. Previously extremem would be Atkins Induction, which has plenty of fat.

  18. Dear Katrina, I was on the attack phase for 2 days and had a blood test on the 3rd day after developing chest discomforts on the left side through the night. Although the ECG results were fine, the blood test revealed a higher than average bilirubin level. I’m also wondering if it’s the effect of the all protein diet. Have you had any feedback so far?

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