The Dukan Diet: A Dietitian Breaks Down Everything to Know

When it comes to weight loss, getting rid of pesky pounds and journeying toward your goal weight is the first part of the process. Once you accomplish this, the next part is maintaining it. It all comes down to following nutritious eating habits, leading a healthy lifestyle, and getting regular exercise. In the wide world of weight-loss diets, you've likely heard of many that claim to yield results, such as the Dukan diet, a high-protein, low-carb eating regimen that celebrities like Jennifer Lopez and Kate Middleton have reportedly tried. Should you try the Dukan diet for weight loss? Well, we spoke with Amy Goodson, MS, RD, CSSD, LD, a registered dietitian and certified specialist in sports dietetics who sits on our Medical Expert Board, who breaks down everything you should know about it.

It's important to keep in mind that there's no one-size-fits-all approach to weight loss. It's always wise to check in with a registered dietitian or your healthcare provider before starting a new diet so they can weigh the pros and cons and determine if it's a solid fit for you.

What is the Dukan diet?

The Dukan diet was brought to life by French medical doctor Pierre Dukan who has 40 years of clinical nutrition experience under his belt, according to the official Dukan diet website. This eating regimen is broken down into four phases with two steps to drop excess weight and two steps that claim to "keep it off forever," the website explains.

What are the four stages of the Dukan diet?

The Dukan diet consists of four phases:

Attack Phase: The first phase is all about consuming a substantial amount of lean protein from the diet's list of 68 high-protein foods.
Cruise Phase: The second phase introduces 32 non-starchy vegetables into your meals. Dieters will alternate between "pure protein" days and "protein plus vegetable" days.
Consolidation Phase: The third phase slowly reintroduces other food groups and certain indulgences into your diet, allowing for up to two "celebration meals" each week. This phase also calls for having a "pure protein" day on Thursday.
Stabilization Phase: The fourth and final phase aims to help keep pesky pounds at bay through the eating habits and patterns dieters learn while on the Dukan diet. This phase also stresses certain "non-negotiable rules" to stick with, including having three tablespoons of oat bran daily, walking for 20 minutes each day (and opting for the stairs whenever you can), and doing "pure protein" on Thursday.

What foods can you eat on the Dukan diet?

"The Dukan diet allows specific types of lean protein (such as chicken, fish, lean beef, and tofu), non-starchy vegetables, and small amounts of oat bran," explains Goodson. "Foods like fruits, starchy vegetables, and high-fat dairy are limited or restricted."

On the Dukan diet, you're able to eat as much as you please of 100 foods (68 "pure proteins" and 32 nonstarchy vegetables) determined by Dr. Dukan that are packed with protein and low in fat and carbs. As seen above, the restrictions get a little more lenient as you reach the Consolidation Phase. When you're in the final phase, no foods are off limits, but you still need to be mindful of your eating habits.

Foods you can eat on the Dukan diet:

Lean meat (such as pork, beef, and lamb)
Fish (arctic char, tuna, swordfish, haddock, etc.)
Shellfish
Poultry (chicken, turkey, etc.)
Vegetarian proteins (tofu, tempeh, and seitan)
Eggs
Fat-free dairy (cottage cheese, Greek yogurt, sour cream, milk, etc.)
Nonstarchy vegetables (broccoli, artichoke, beets, eggplant, cauliflower, peppers, tomatoes, onion, spinach, etc.)
Oat bran (small amounts)
Water

Foods you should avoid or limit on the Dukan diet:

Fruit
Carbs and grains
Starchy vegetables
Cheese
Alcohol

Can the Dukan diet help you lose weight?

woman's feet on scale, concept of how to lose one pound — Shutterstock

If you're wondering if the Dukan diet can help you lose weight, Goodson confirms it can. "Many people have reported weight loss success with the Dukan diet, especially during the initial phases, due to its restrictive nature and focus on protein-rich foods," she says. "However, it is important to note that it is very restrictive and likely not sustainable for most people to follow to maintain weight loss over time."

What are the dangers of the Dukan Diet?

Overall, it's crucial to note that while the Dukan diet could lead to fast weight loss, it's not a particularly healthy way to lose weight for several reasons, including posing potential health risks.

There's a lack of well-balanced nutrition. According to Goodson, the Dukan diet may not offer all essential nutrients because it's so restrictive.
It poses potential health concerns. Sticking with a low-carb, high-protein diet like Dukan could make you more susceptible to various health issues, lead to a lack of energy, and contribute to nutrient deficiencies.
It's unsustainable. Sustainability is key when weight loss is the goal, and some individuals might find the strict rules under this diet challenging to stick with in the long run. This can lead to regaining the weight you worked so hard to lose.
It doesn't have much scientific evidence behind it. "While some studies suggest short-term benefits, there's limited long-term research on the effectiveness and safety of the Dukan diet," explains Goodson.