What Is the Dukan Diet?

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The Dukan Diet is a low-carbohydrate, high-protein weight loss program developed by a French physician in the 1970s. The plan includes four phases—Attack, Cruise, Consolidation, and Stabilization. Two phases focus on weight loss and the other two focus on maintaining that loss.

The plan is based on the premise that you don't lose weight when you are hungry. It provides specific lists of foods that are allowed in different phases with a focus on lean proteins and fat-free dairy, which boost satiety.

According to proponents of the Dukan Diet, you can expect to lose up to four to six pounds in the first week on the Attack Phase, and two pounds a week on the Cruise Phase. During the Consolidation and Stabilization phases, you will work on maintaining that loss.

What Experts Say

"Protein is one of the most satiating nutrients, so you’ll likely feel full on this program, but there are a lot of 'food rules' to follow. The diet is heavy on animal proteins—chicken, eggs, dairy, beef, fish, etc.—making it difficult for plant-based eaters."

Kelly Plowe, MS, RD

Background

The diet was created by Paris physician Pierre Dukan, M.D., in the 1970s to help his obese patients lose weight. At the time, the primary diet prescribed for weight loss consisted of low calorie, small-portion meals, which was difficult for his patients to follow. 

Dr. Dukan's plan focused on lean protein, which reduces hunger making it easier to stick to. Over the next 20 years, he further developed the plan into four phases, publishing the Dukan Diet in the New York Times best-selling book Je ne sais Pas Maigrir (I Don't Know How to Get Slimmer) in 2000. 

The diet has been criticized as a fad diet and health professionals say it increases the risk of chronic kidney disease and may worsen cardiovascular health. Dukan stopped practicing medicine in 2014.

How It Works

Unlike other low-carb diets, such as keto and Atkins, the Dukan Diet is also very low in fat. In Dukan’s philosophy, fats are worse than carbohydrates and represent a danger to health. 

The majority of calories and nutrients on the Dukan Diet come from protein, which is more filling than carbohydrates with fewer calories than fat. In addition to diet, the plan encourages physical activity, particularly walking and taking the stairs instead of the elevator.

A unique component of the Dukan Diet is the "True Weight" calculator, which factors in your weight history, gender, age, bone structure, and other parameters to determine a realistic weight-loss goal that can be maintained for life.

The diet is divided into four phases:

Phase 1: Attack

The first phase of the Dukan Diet lasts two to seven days, depending on how much weight you need to lose. During the Attack Phase, you can eat unlimited lean protein—lean beef, skinless poultry, seafood, and eggs—along with limited low-fat dairy, a small amount of olive oil for greasing pans, and 1.5 tablespoons of oat bran a day.

The diet refers to this as "Pure Protein" days. The reduction in carbs helps to switch the body from burning sugar for energy to using ketones, putting the body into ketosis. It also requires drinking six to eight glasses of water a day.

Phase 2: Cruise 

This phase begins as early as day 2 of the diet or as late as day 8 (under medical supervision for people who need to lose 40 pounds or more) and lasts for up to a year.

During the Cruise Phase, you will continue to eat the foods on the Attack Phase, with specific vegetables added in, such as leafy greens, broccoli, cauliflower, peppers, cucumbers, and mushrooms. You will also increase oat bran to 2 tablespoons per day. Some days are "Pure Protein" days and others are "Protein/Vegetable" days.

Phase 3: Consolidation

Once you reach what Dr. Dukan calls your "true weight," the consolidation phase begins. The length of this period depends on the amount of weight you have lost, with five days of consolidation for every pound dropped.

During the Consolidation Phase, you will continue to eat the foods from the earlier two phases, and add in small servings of fruit, bread, starches, cheese, other cuts of meat, and wine. You will also increase oat bran to 2.5 tablespoons per day. One day each week is devoted as a "Pure Protein" day where you follow the attack phase menu.

Phase 4: Stabilization

The final phase is the weight maintenance part and lasts indefinitely. During the Stabilization Phase, you will follow the Consolidation Phase guidelines but loosen the rules as long as your weight remains stable.

A 2015 study of 51 women who followed the Dukan Diet for eight to 10 weeks found they ate about 1,000 calories and 100 grams of protein a day, and lost about 33 pounds. Dietary intake was high in potassium, iron, and vitamins A, D, and B2, but low in vitamin C and folates. The study, however, was small and has not been reproduced.

What to Eat

The Dukan Diet allows 68 low-fat, protein-rich foods in the first phase with 32 non-starchy vegetables added during the second phase. Here's a look at what you can and cannot eat during the Cruise Phase, which is the majority of the plan. Non-compliant foods are added back in during the Consolidation and Stabilization Phases.

Compliant Foods

  • Lean beef, pork, veal, venison, bison, and other game

  • Skinless poultry

  • Fish and shellfish

  • Eggs

  • Non-fat dairy including milk, yogurt, cottage cheese, and ricotta (in limited amounts)

  • Tofu, tempeh, and seitan

  • Liver, kidney, and tongue

  • Oat bran

  • Artificial Sweeteners

  • Shirataki noodles

  • Diet gelatin

  • Lemon juice

  • Pickles

  • Olive oil

  • Leafy greens, like spinach, kale, and lettuce

  • Broccoli, cauliflower, cabbage, and Brussels sprouts

  • Bell peppers

  • Asparagus, artichokes, cucumbers, and celery

  • Eggplant, tomatoes, and mushrooms

  • Onions, leeks, and shallots

  • Spaghetti squash

  • Pumpkin

  • Green beans

  • Turnips

  • Carrots and beets (in limited quantities)

Non-Compliant Foods

  • Bread, pasta, and rice

  • Legumes

  • High-fat meats, like bacon

  • Sugar

  • Alcohol

  • Fruit

  • Non-skim dairy

  • Butter

  • Nuts

  • Cheese

  • Fried foods

  • Salad dressing, mayonnaise, and sweetened condiments

  • Potatoes

  • Avocados

Recommended Timing

The Dukan Diet does not require fasting or complicated meal timing, but it does restrict different foods to certain days.

During the Cruise Phase, you will alternate between days of eating just protein ("Pure Protein" days) and eating protein and vegetables ("Protein/Vegetable" days). The plan calls this "alternation" and these cycles are used to boost metabolism and jump-start weight loss.

Alternation cycles range from one to fives days of pure protein followed by the same number of days of protein and vegetables. Longer alternation cycles are recommended for people who have a lot of weight to lose or when weight loss plateaus.

During the Consolidation Phase, one day each week is devoted to Pure Protein.

Resources and Tips

More information about the Dukan Diet is available on its website, dukandiet.com, which offers personalized coaching for $30 a month.

In addition, Dr. Dukan has several books outlining the plan:

  • The Dukan Diet Made Easy
  • The Dukan Diet Book
  • The Dukan Diet Cookbook

Pros and Cons

Pros

  • All-you-can-eat of certain foods

  • Filling

  • Quick weight loss

  • Focus on weight maintenance

Cons

  • Strict rules

  • Missing nutrients

  • May negatively impact kidney and cardiovascular health

Pros

The Dukan Diet is effective for quick weight loss and sets realistic expectations for sustained weight loss with its "True Weight" concept. In addition, the plan allows for unlimited amounts of lean protein, which is filling and means you won't go hungry.

The diet also has a long consolidation phase, which helps the transition from weight loss to long-term maintenance. Our bodies tend to resist maintaining fat loss and having a fairly long period of time focused on keeping weight stable can help keep the pounds off for good.

Cons

The primary concern with the Dukan Diet is it restricts several foods, which may make it difficult to get adequate nutrition. About half of the days in the weight-loss phase are pure protein, with no vegetables allowed, so many vitamins, minerals, and phytonutrients are lacking. Supplements are allowed on the plan, but not required.

Salt is also minimized on the diet, which reduces the palatability of meals, making it more difficult to stick to. Additionally, some people need to eat more salt during the first weeks of a low-carb diet as sodium is lost along with water weight.

The diet introduces some contradictory concepts. For example, vegetables are restricted to low-starch varieties, but fat-free dairy, which is higher in sugar and carbohydrates, is allowed up to 32 ounces a day. Dr. Dukan brushes aside the milk sugars in these products, saying the number of sugars is too small to worry about. But then he restricts low-starch vegetables, which are even lower in sugars/carbs.

In addition, there are many statements of "fact" in the book that are either false or highly questionable. Here are a few:

  • Dr. Dukan calls the carbohydrates in root vegetables and whole grains "slow sugars," meaning they break down into sugar slower than refined grains and sugars, but this is misleading. Many starchy vegetables raise blood sugar even faster than refined sugars, and the carbohydrates in any grain that is ground into flour, whether whole or not, raises blood sugar quickly.
  • He states that the Atkins Diet causes "cholesterol and triglyceride levels to rise dangerously." However, the opposite has been widely documented.
  • Additional claims that are not scientifically backed include that fat reserves turn into glucose for energy, that there is a golden proportion of macronutrients and deviating from the proportion promotes weight loss, and the combination of water and pure proteins act powerfully on cellulite.

How It Compares

The Dukan Diet is an effective weight-loss plan, however, many find it too restrictive and difficult to follow. It is high in protein and low in carbohydrates and fats, which may lead to nutrient deficiencies and health complications.

The 2019 U.S. News and World Report Best Diets ranks the Dukan Diet number 41 in Best Diets Overall and gives it an overall score of 1.9/5.

Its low ranking—41 out of 41 diets reviewed—is based on its strict rules that are difficult to follow, possible health risks, and unsustainability for long-term weight loss.

USDA Recommendations

The United States Department of Agriculture (USDA) dietary guidelines include calorie recommendations and tips for a healthy, balanced diet. The Dukan Diet does not meet these guidelines.

The National Academy of Sciences, which carefully reviews the research and sets the USDA dietary guidelines, currently recommends 10 percent to 35 percent of calories come from protein—or 0.8 g of quality protein per kilogram of weight. On The Dukan Diet, however, 79 percent to 90 percent of calories come from protein. 

The main concern with eating too much protein is that our livers and kidneys have to work to process the byproducts of protein metabolism, and there is a limit to how much protein they can deal with. Dr. Dukan says drinking a lot of water will take care of this problem, but he doesn't provide any references to back this up.

In addition, people often don't feel very good eating an all-protein diet and can experience gastrointestinal disturbances, headache, low blood pressure, and malaise, along with bad breath

Similar Diets

The Dukan Diet is similar to both the Atkins Diet and keto diet, with a few differences. All three are low-carb plans that put the body into the fat-burning state of ketosis and are effective for short-term weight loss.

Atkins Diet: Like the Dukan Diet, the Atkins Diet also has different phases— starting with less than 20g of carbs a day, increasing to 100g a day, and ending with a maintenance phase. It is higher in fat than the Dukan Diet, but allows for more flexibility and food options, which may make Atkins easier to follow.

Keto Diet: The keto diet, short for ketosis, aims to keep carbohydrates at 20g or less per day to keep the body in fat-burning ketosis, a state where the body switches from burning glucose to ketones for energy. Unlike Dukan and Atkins, keto also limits protein and focuses more on fat because excessive protein can be converted to glucose, kicking the body out of ketosis.

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