The Dukan diet is a controversial, complicated diet that is low in calories, carbohydrates and fat, but high in protein. It was created by French physician Dr. Pierre Dukan in the 1970s. Dukan was a general practitioner until 2014, when he lost his medical license in France for violating ethical regulations.
Here’s everything you need to know about the Dukan Diet, including how it works and whether it’s a safe and effective way to lose weight.
The Dukan diet is a low-carb, low-fat, and high-protein diet that restricts a number of healthy foods and is primarily based on protein and vegetables. It is split into four stages, each with its own intricate rules.
The first two phases are designed to promote weight loss, while phases three and four are for weight stabilization and maintaining one’s “true weight.” Dukan suggests that a person’s true weight is a healthy and realistic weight that can be maintained for life.
Here’s more about the four phases of the Dukan diet.
The attack phase
The attack phase is the first phase of the diet. How long a person stays in this phase depends on the weight they want to lose, their age, and their nutritional history. For most people, this phase lasts two to five days.
Here are the timing recommendations listed on the Dukan website:
- Less than ten pounds to lose: one or two days
- From 15 to 30 pounds to lose weight: three to five days
- Losing more than 40 pounds: After consulting your doctor, this phase can last up to seven days.
During the attack phase, a person is only allowed to eat 68 approved high-protein foods, such as skinless chicken breasts, eggs, and low-fat dairy products. It is recommended to consume 1.5 tablespoon of oat bran per day to prevent constipation and limit calorie intake.
In the attack phase, it is recommended to add physical activity in the morning, such as walking.
The cruise phase
The Cruise phase is meant to be followed until you reach your “true weight”. You are supposed to follow this phase for three days for every kilogram you want to lose. If a person has more weight to lose, they will remain in the cruise phase for a longer period of time.
During the cruise phase, all foods from the attack phase are allowed, plus 32 non-starchy vegetables, including zucchini and greens, creating a list of 100 allowed foods. It is recommended that you alternate pure protein (PP) days – which consists of eating only foods approved in the attack phase – with protein and vegetable (PV) days. Oat bran is also encouraged during this phase.
It is also recommended to exercise daily to stimulate fat loss. Dukan recommends 30 minutes of brisk walking per day.
The consolidation phase
The consolidation phase marks the end of the weight loss phases and allows for the introduction of new foods. It is recommended to stay in this phase for ten days for every kilogram lost. People who lose more weight in the first two phases stay longer in the consolidation phase.
In addition to the 100 foods allowed in the first two phases, fattier cuts of meat and unsalted cooked ham are allowed.
The following table explains the other foods allowed during the consolidation phase. Please note that the consolidation phase is split into two parts.
| Additions in the first half of Consolidation | Additions in the second half of Consolidation |
| One serving of fruit every day, except bananas, figs, cherries and grapes | 2 servings of fruit per day, except bananas, figs, cherries and grapes |
| 2 slices of wholemeal bread per day | 2 slices of wholemeal bread per day |
| 1.5 ounces hard rind cheese | 1.5 ounces hard rind cheese |
| 1 serving (cooked cup) of starchy foods per week | 2 servings (boiled cup) of starchy foods per week |
| 1 festive meal per week, consisting of a starter, an entrée, a dessert and a glass of wine | 2 festive meals per week, consisting of an appetizer, an entrée, a dessert and a glass of wine |
The stabilization phase
This phase is intended to be followed for life to promote weight stabilization. No food is off limits, but a person must adhere to three rules:
- Eat three tablespoons of oat bran every day
- Have one Pure Protein day per week where you only eat phase one foods
- Take the stairs and avoid elevators and escalators
Dukan recommends that dieters sign up for coaching through the Dukan website to increase the likelihood of long-term success.
Any diet that significantly restricts calories will result in weight loss, so it is likely that a person following the highly restrictive Dukan diet will experience fat loss.
Not many studies have looked at the effects of the Dukan diet on weight loss, but a 2015 study found that women who followed the Dukan diet for eight to 10 weeks lost an average of 33 pounds.
However, the researchers found some key issues with the diet, such as inadequate vitamin and mineral levels and excessive protein intake. In addition, the reason for the significant weight loss was thought to be due to the diet’s extremely low calorie content.
The study found that the women on the Dukan diet consumed only 888 calories per day during the first phase of the diet and about 1,000 calories per day during the other phases. Any diet this low in calories will result in rapid weight loss, but it’s not a healthy or sustainable way to lose weight.
The study didn’t follow the women long-term, but chances are the weight they lost gained back over time. Studies show that people who lose weight by following restrictive diets usually regain most or all of the weight they initially lost.
In addition to weight loss, the Dukan diet can also lead to short-term reductions in blood sugar and blood lipid levels. However, this is due to the extreme calorie restriction and rapid weight loss encouraged by this diet, not necessarily the diet itself.
There is currently insufficient evidence to support the use of the Dukan diet for promoting weight loss or improving other characteristics of health. Because the diet is so restrictive and not based on sound science, it is best to avoid this diet and instead choose more evidence-based methods to improve health.
The Dukan diet is very restrictive and significantly cuts calories, which can lead to several health risks.
A 2014 case study reported that a woman on the Dukan diet was hospitalized because she experienced uncontrollable vomiting due to ketoacidosis. Diet-induced ketoacidosis is a rare condition caused by a lack of glucose, or blood sugar, in the body.
While it’s unlikely you’ll develop ketoacidosis if you follow the Dukan diet, this eating pattern can lead to a host of other unpleasant and potentially dangerous side effects.
Studies show that cutting calories and carbohydrates too much can lead to side effects such as dizziness, irritability, headache, fatigue, extreme hunger, low blood sugar and constipation.
In addition, the 2015 study mentioned above found that the women following the Dukan diet had low intakes of several nutrients, including vitamin C, potassium, calcium and folate, and consumed excessive amounts of protein, phosphorus and sodium.
Because it is so restrictive and low in calories, the Dukan diet is not suitable for children, teenagers, pregnant or breastfeeding women, and people with certain medical conditions, such as eating disorders and low blood pressure.
There are many other weight-loss friendly eating patterns that are safer and less restrictive than the Dukan Diet and provide your body with the nutrients it needs to function optimally. If you want to lose weight or improve other health parameters, it is best to opt for an evidence-based, nutritious diet such as the Mediterranean diet or a completely plant-based diet.
The Dukan diet is a low-carb, low-fat, high-protein, low-calorie diet. It is broken down into four stages, most of which are excessively restrictive.
It is likely to lead to short-term weight loss, but it is not based on sound science and can lead to various side effects, which can be dangerous.
If you’re interested in losing weight, consider following a more sustainable diet that doesn’t involve extreme calorie restriction or rely on arbitrary and complicated rules.
If you need help choosing an effective weight loss plan, consider working with a registered dietitian to come up with a plan that is safe and healthy for your body.