How the Dukan Diet Works

by | Apr 21, 2010 12:27 PM ET

Are you looking for a diet that will take off the pounds and keep them off? People in France seem to have this figured out - the French are significantly less obese than Americans. Why is that? The following article offers a possible explanation:

The answer could lie in their diet. Not the olive oil and red wine Mediterranean diet so popular on the Continent, but a striking weight-loss programme that has been taking the country by storm.
When eminent French nutritionist Dr Pierre Dukan introduced his Dukan Diet there ten years ago, the book rushed to the top of the French best-seller list and spawned an underground dieting revolution of 200 websites, forums and blogs.

The article then goes on, in three parts, to describe the Dukan Diet (or as it is known in France, Régime Dukan):

1) The ultimate diet:The French have kept it a secret for years. Now the protein rich Dukan Diet is coming to Britain

2) The Dukan Diet: Put your fat cells on a revolutionary weight-loss plan

3) The Dukan Diet: Want to stay slim for ever? Eat whatever you want - except on Thursdays

Like any diet, this French protein diet sounds too good to be true: "It acknowledges the innate pleasure to be had from eating and, incredibly, promises efficient weight loss while eating unlimited quantities of real food." It sounds like pie-in-the-sky. Yet I have found that this diet really does work (and you can see my progress below - I have lost more than 50 pounds on this diet and have a day-by-day diary below to show you how it happened - you can see before and after photos here). If you would like to consider it, here is a summary of how this diet works:

- Phase 1: Also known as the Attack phase. You eat low-fat protein only. And drink a lot of water (coffee, tea and diet sodas or OK too but they have to be zero calories and zero fat).

Your protein is likely to come in the form of meat (low-fat beef, chicken, turkey, fish), but there are also dairy possibilities (e.g. zero-fat yogurt and cottage cheese, etc) and vegetarian/vegan options (e.g. eggs, tofu and seitan). You can season your protein with anything that is zero fat and zero carbs, like salt, vinegar, onions, mustard, normal spices (oregano, basil, pepper, etc.) and so on. You also add some oat bran (1.5 tablespoons per day) to the mix and a 20-minute walk every day.

In the attack phase, the only thing that will passing your lips is the protein, the oat bran and the water.

Unlike the Atkins diet, the goal is low-fat meat. The article claims that in the first 5 days of eating nothing-but-protein, you could lose between 7 and 10 pounds. See the second article above for details.

(OK - I actually tried a five-day attack phase myself to see what would happen, and I lost 6.6 pounds. Click here if you want to see how it went.)

- Phase 2: Also known as the cruise phase. You have days of nothing-but-protein alternated with days of nothing-but-protein-and-vegetables. Salad is included as a vegetable. You continue the oat bran (2 tablespoons per day), the water and the walking (which increases to 30 minutes a day, briskly). You can see why the Dukan diet is also known as the French protein diet.

You get to pick how you mix the nothing-but-protein days with days of nothing-but-protein-and-vegetables. Some of the mixes you will read about are 5 days of protein only alternated with 4 days of protein and veggies. Or 4/3. Or you could try other combinations.

Phase 2 could last for months if you have a lot of weight to lose. How do you know how long you need to be in Phase 2 and when it is time to switch to Phase 3? Also, how do you calculate your correct target weight (which is what marks the end of Phase 2)? You use the calculator on One stone equals 14 pounds, by the way. So if you weigh 140 pounds, you weigh 10 stone. If you weigh 142 pounds you weigh 10 stone and 2 pounds. See also: What is your “ideal weight” if you want to be healthy?.

What does the menu look like in Phase 2? The vegetables you are allowed to eat are pretty limited, because some things that we consider "vegetables" actually contain a lot of carbs. Things like carrots, peas, corn and potatoes are out, therefore. Green is in. So anything you might normally find in a salad is OK, including: Lettuce, spinach, broccoli, cucumbers, tomatoes, bell peppers, mushrooms, onions. Also allowed are things like green beans, cabbage, cauliflower, asparagus and celery. You can eat them raw, or steam them, or boil them. Your menu could include soups or stews that combine protein and vegetables. The menu will definitely include salads. This site has some recipes for salad dressings, including Vinaigrette Salad Dressing and Creamy Salad Dressing.

(OK - I went through 25 weeks of "Cruise Phase" myself to see what would happen. Here is my diary of the process (I have lost more than 50 pounds):

- Week 1 (I lost 2.8 pounds)

- Week 2 (I lost 5.4 pounds)

- Week 3 (I lost 2.6 pounds)

- Week 4 (I lost 2.4 pounds)

- Week 5 (I lost 3.0 pounds)

- Week 6 (I lost 1.8 pounds)

- Week 7 (I lost 2.6 pounds)

- Week 8 (I lost 2.2 pounds)

- Week 9 (I lost 2.6 pounds)

- Week 10 (I lost 1.6 pounds)

- Week 11 (I lost 1.2 pounds)

- Week 12 (I gained 1.0 pounds on vacation)

- Week 13 (I lost 3.2 pounds)

- Week 14 (I lost 0.4 pounds)

- Week 15 (I lost 2.8 pounds)

- Week 16 (I lost 2.0 pounds)

- Week 17 (I lost 0.8 pounds)

- Week 18 (I lost 3.4 pounds)

- Week 19 (I gained 0.8 pounds)

- Week 20 (I lost 2.0 pounds)

- Week 21 (I lost 2.0 pounds)

- Week 22 (I gained 2.0 pounds)

- Week 23 (I lost 3.6 pounds)

- Week 24 (I gained 0.8 pounds)

- Week 25 (Success! I lost 1.8 pounds and reached my goal. Includes before and after pictures)

- Phase 3: Also known as the consolidation phase, this phase starts once you reach your target weight. You don't lose any weight here - you just maintain your new weight. The consolidation phase adds a little fruit, bread and cheese to the mix, as well as one "celebration meal" per week. See article 3 above for details. If you mine through the article you find that a typical menu for the week looks like this:

1) Continue eating protein plus vegetables to your heart's desire. They are always on the menu.

2) You get one fruit a day, but you are looking for the watery fruits like watermellon, cantelope, apples, etc.

3) You get two slices of whole-grain bread. If you must have butter, make it low-fat. Be stingy with the butter.

4) You get one serving of carbs per week. This might be pasta or rice.

5) Your menu expands to include one "celebration meal" per week, where anything goes. But really, if you are losing a significant amount of weight, it has been 6 or 8 months since you had real food. Do you really want to blow it now? I guess if you travel, this meal would allow you to eat one normal restaurant meal a week. As you move to the second half of Phase 3, you get two of these "celebration meals" per week.

What does all this protein cost? See this page for details.

(OK - I have started the "Consolidation Phase" myself to see what would happen. Here is my diary of the process so far:

- Week 1 (I lost 0.2 pounds - 175.2)

- Week 2 (I gained 2.2 pounds - 177.4)

- Phase 4: The article is a little ambiguous here. It says, "Go back to eating whatever you like, but continue to use the basic rules of the Consolidation Phase as a safety platform (eat unlimited protein and vegetables, one piece of fruit a day, two slices of wholemeal bread, a portion of cheese, two starchy foods and two celebration meals a week)." There is a huge difference between "eating whatever you like" and eating the Phase 3 diet. So let's summarize: Eat a phase 3 diet, except on Thursday. On Thursday you eat nothing-but-protein. You continue walking every day. See article 3 above for details.

When I try the calculator, it tells me my target weigh is 13 stone 2 pounds and I should be there in August.

If you take a look at How the Atkins Diet Works, you will notice an eerie similarity between the Dukan diet and the Atkins diet. The 4 phases are the same. The emphasis on protein and the lack of carbs is the same. The Dukan diet looks a lot like the Atkins diet minus the fat that the Atkins diet allows. See this page for the benefits and drawbacks of the Atkins diet.

A cohort at HSW had some questions about the downsides, problems and side-effects of the Dukan diet, so let's go through those:

1) What are the health effects or problems of the Dukan diet? Any side-effects?

When you look at the health effects of any diet, you have to weigh the tradeoffs. For example, obesity is a big health problem because it can lead to an increased probability of high blood pressure, diabetes, heart attack and stroke. If you can lose a lot of weight, those risks generally decline and that's a good thing.

As mentioned above, the Dukan diet is similar to the Atkin's diet, and there has been fairly extensive research on the health effects of the Atkin's diet. This article summarizes some typical problems that people encounter, including:

- Gout - The article Gout in-depth lists a number of factors that lead to gout, including age, gender, family history, obesity, certain medications and alcohol consumption. A high-protein diet may increase the liklihood of gout, but as you can see it is just one of many factors. If you fit the profile, this diet may not be for you.

- Headaches or Dizziness - Some people have an initial reaction to the loss of carbs in the diet. If you don't see these symptoms going away in a day or two, this diet might not be for you

- Cholesterol problems - generally speaking, losing weight helps cholesterol long-term, although cholesterol may go up during the initial part of the diet. Sticking to non-red meats (e.g. chicken and fish) lowers cholesterol intake. There is a decent chance that your cholesterol will eventually go down on this diet. But if your doctor has you on cholesterol or BP medication, you should mention the diet to your doctor so he/she knows about it and can offer advice.

2) Isn't all that meat going to make you constipated?

During the attack phase and on nothing-but-protein days, the high concentration of protein in the diet might cause constipation in some. Note that you are asked to drink a lot of water and to take oat bran as part of the Dukan diet - both are designed to relieve constipation. However, if a constipation problem arises, this diet may not be for you, or you might need to skip the attack phase and go straight to the meat-plus-veggies phase.

3) Aren't you just going to gain all the weight back once you end the diet?

If, after losing the weight, you go back to eating 4,000 calories per day, then yes, you will gain all the weight back. But the intent is that you will not do that. If you were to stick with this diet as designed, the idea is that the consolidation phase changes your eating habits and exercise habits while maintaining a stable weight. Also, the nothing-but-protein-on-Thursdays idea is designed to counteract mild overeating. The success of this diet, and any diet really, depends on your ability to change eating and exercise habits. See How Dieting Works for more info.

4) Are there people who really shouldn't be doing this diet?

As mentioned above, you should talk to your doctor about this diet or any diet. If you have a family history of gout, severe constipation or cholesterol fluctuations, these are concerns you should definitely discuss with your doctor.

5) What about kidney failure? Won't your kidneys fail eating all that protein?

I haven't seen any evidence of kidney failure - as best I can tell this is an urban legend that has grown up around low-carb diets. See these two articles for a discussion:

See also:

- Yesterday I finished a five-day “Attack Phase” on the Dukan Diet – here's a report on how it went

- I have finished the first five days of the “Cruise Phase” on the Dukan Diet – here is a report on how it went, plus a menu for a typical protein day

- I have finished my second week on the Dukan Diet “Cruise Phase” and lost 5.4 pounds during the past seven days. Here is a report on how it went, and a “secret ingredient” that may have helped.

- A report on week 3 of the Dukan Diet Cruise Phase. The whole thing has become a straightforward habit, and the weight loss seems very consistent

- I finished my fourth week in the Dukan Diet Cruise Phase and lost another 2.4 pounds – plus I saw an amazingly good blood pressure reading

- I have finished my fifth week in the Dukan diet cruise phase and lost another 3.0 pounds – and now I know the secret to avoiding calories in an Italian restaurant

- In my sixth week on the Dukan Diet Cruise phase I lost “only” 1.8 pounds, and I am now halfway to my 50 pound goal

- Today I finished my seventh week on the Dukan Diet cruise phase and lost 2.6 pounds – I have almost broken through the 200 pound barrier

- Dukan diet Cruise Phase Week 8 – wherein I learn the perils of parties

- Dukan diet Cruise Phase (Phase 2) week 9 – I've lost 32.0 pounds with no “plateaus”

- Dukan diet Cruise Phase (Phase 2) week 10 – Lesson: Don't eat smoked turkey legs!

- Dukan diet Cruise Phase (Phase 2) week 11 – Are my kidneys failing? Is my cholesterol exploding? Plus vacation.

- Dukan diet Cruise Phase (Phase 2) week 12 – Vacation transgressions take their toll and I gain weight for first time

- Dukan diet Cruise Phase (Phase 2) week 13 – I get back on track and lose 3.2 pounds in a week

- Dukan diet Cruise Phase (Phase 2) week 14 – I lost 0.4 pounds this week

- Dukan diet Cruise Phase (Phase 2) week 15 – I lost 2.8 pounds this week, 40.2 pounds since starting diet

- Dukan diet Cruise Phase (Phase 2) week 16 – I lost 2.0 pounds, have reached my Dukan target weight

- Dukan diet Cruise Phase (Phase 2) week 17 – I lost 0.8 pounds, learned to stay out of Cici's

- Dukan diet Cruise Phase (Phase 2) week 18 – I lost 3.4 pounds, now in striking range of the 170s

- Dukan diet Cruise Phase (Phase 2) week 19 – One really good day and one really bad day

- Dukan diet Cruise Phase (Phase 2) week 20 – I tasted the 170s for one day and it felt great

- Dukan diet Cruise Phase (Phase 2) week 21 – I hit the 50.0 milestone and reaffirmed the power of asparagus

- Dukan diet Cruise Phase (Phase 2) week 22 – Yikes! I gained 2.0 pounds rather than losing weight

- Dukan diet Cruise Phase (Phase 2) week 23 – I lost 3.6 pounds and now fit into 32-inch pants

- Dukan diet Cruise Phase (Phase 2) week 24 – I am a little bit stuck this week

- Dukan diet Cruise Phase (Phase 2) week 25 – I have reached 175 pounds, before and after pictures, heading to Phase 3!

- What is your “ideal weight” if you want to be healthy?

- What if everything that we are taught about carbs is actually propaganda?

- How much does the Dukan Diet cost per day?

- Today I officially reached the “50.0 pounds lost” milestone on my Dukan Diet journey – and you can too

- How does your appearance change when you become obese?

- Drew Carey loses 80 pounds with a no-carb diet

- Would you like to lose weight? Video shows the latest science on what works and doesn't

- How to do proper crunches to (theoretically) get six-pack abs

- What can you do when you “get stuck” at some weight plateau on the Dukan diet (or any diet)

- How Carbohydrates Don't Work – in fact, carbs are probably causing the obesity epidemic. If you are overweight, it is probably the carbs.

- All the dire warnings I have gotten about the Dukan diet have turned out to be wrong

- Very cool calculator for calculating your specific dietary needs – Protein, carbs, fat, vitamins, etc.

- How Treadmills and Exercise Bikes Don't Work – if weight loss is your goal, High-Intensity Interval Training (HIIT) is a better option

- This has got to be the easiest weight loss tip ever

- When a person is fat, how is the fat distributed in the body (amazing x-rays)?

- Why America is obese #1 and Why America is obese #2 and Why America is obese #3

- How Seitan (also know as Wheat Meat) Works - a vegetarian form of protein made from wheat gluten

- How to make tofu

- How to make Greek yogurt at home and cut your yogurt costs in half and I made half a gallon of Greek yogurt this weekend – talk about cheap and easy! And Tasty!


1) How to live to be 100 years old

2) How Cholesterol Works – The leading cause of the #1 killer

3) How Dieting Works

PS - The article starts with this sentence: "Have you ever wondered why most French women appear to be so effortlessly chic and slender, whatever their age?" So the first question to ask is, "Is that true? Do French women have any advantage over the rest of us when it comes to obesity?" This page would seem to indicate that they do. French women are definitely doing better than the majority (although Italian women seem to be doing much better than the French according to the chart).

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