When I first read about the Dukan Diet I thought it was some huge practical joke, but no, it’s yet another best-selling diet book that has sold millions of copies worldwide. And like several best-selling diets before it, the mantra is high protein, low carbs.

The Dukan Diet was created by Dr Pierre Dukan, a medical doctor in France, who specializes in nutrition.

This diet has 4 phases, and they’re very dynamic and sensible sounding too. The marketing and packaging of this diet is fantastic, right down to the names of its 4 phases.

Phase 1 – Attack Phase

Brilliant! I feel empowered already. I’m going to attack my obesity with 5 days of low fat protein, water, and….. oh, and nothing else, except 1.5 tablespoons of oat bran per day.

One of the many strange things about this diet is that the first 5 days prohibits all vegetables. No wonder this diet is so popular with anyone who hates eating healthily. Vegetables are a pretty important part of healthy eating, because of their vitamins, minerals, phytochemicals, but also because of their fibre content. Insoluble fibre helps bowel movements, mops up toxins, and reduces the risk of bowel cancer. And soluble fibre helps lower your LDL (bad) cholesterol levels. The required 1.5 tablespoons of oat-bran is not enough fibre to compensate.

Another odd thing is the demonization of carbohydrates. Sure, you’ll lose weight if you go on a diet with excessive restriction of carbohydrates, and the weight you’ll lose is primarily water, and healthy glycogen stores. You’re also likely to feel a loss of energy, making it hard to exercise optimally. And if that’s not bad enough, some people report bad breath, and constipation from the lack of fibre that complex carbs and vegetables supply.

Did I mention the headaches? This and the low energy and bad breath are explained as all part of the detox phase, according to supporters of the Dukan Diet. You’re like a drug addict coming off the evil drug of carbohydrates. This is a totally false analogy because carbohydrates (as long as they’re unprocessed, unrefined, complex carbs) are an important part of a healthy diet (when I say diet here, I just mean normal healthy eating, not a commercial Diet).

And the bit about eating as much protein as you like is in my opinion totally bonkers. The body can’t process more than around 20-40g of protein at any one time (depending on the size and gender and activity levels of the individual), and the excess is excreted out in the urine, after putting unnecessary strain on the kidneys.

The good thing about this phase is that the proteins recommeded include oily fish, lean chicken, low fat live yoghurt. It’s good to have some protein with every meal, I’m just dubious about the sheer quantities of it you’re permitted to consume.

So far it sounds a bit like Atkins, but as Dr Dukan says, the Atkins diet had no prohibition on fats, whereas Dukan advocates low saturated-fat sources of protein. So the Dukan diet is not nearly as bad as Atkins.

Phase 2 – Cruise Phase

This is another great name, cruise phase, sounds like you’re making real progress, cruising along on your journey to slimness and health. In this phase you alternate a day of protein & water only (and 1.5 tablespoons of oats), then a day of protein & water & vegetables (and the mouse-serving of oats). You continue this until you reach your goal weight.

The good thing about this phase are that you’re now eating vegetables. And to be fair, the first 2 phases do emphasize the importance of  drinking plenty of water. I totally agree with Dr Dukan here, that water is often neglected in our diets, indeed most people are in a constant state of dehydration. With this diet you’ll need plenty of water, to help the kidneys flush out all that excess protein.

Phase 3 – Consolidation Phase

No, this is not a reference to constipation from all that excess protein. Consolidation means you aim to stay at your target weight during this phase. Your ration of oats is increased to two tablespoons a day, and you can add specific foods to phase 2, and you also get two celebration meals per week. You’ll feel like all your Christmases have come at once.

Still not enough complex carbs to sustain any serious gym session. But praise is due to Dr Dukan for emphasizing the importance of plenty of vegetables on an ongoing basis. And equally impressive is the prohibition on alcohol.

Phase 4 – Stabilization Phase

This is the final phase of the diet, which should last for the rest of your life. This is where you can eat what you like, except on Thursday when you go back to Attack Phase for that one day each week. You are also required to eat 3 tablespoons of oat-bran per day (Dr Dukan has a whole book on the subject of oat bran).

Unlike many diet books, Dr Dukan includes an exercise prescription as part of his diet: walk at least 20 minutes a day, and include some stair-climbing. This is excellent advice as far as it goes, but as a personal trainer I advise my clients in London that this is the bare minimum for basic health, and you need more exercise than that to get fit and stay fit.

Finally, does the Dukan Diet work? Many people have lost weight in the initial phases (but how much of this weight is fat and how much is water/glycogen?). More significantly, many find it hard to maintain their goal weight in the final phase. Whether this is because they stop following the instructions or stick to the diet’s prescription and still put on weight I’m not sure. But I think it’s bad to cut out veg (although this is only for the first 5 days), bad to eat so much protein, and bad to cut out complex carbohydrates (the small amounts of oat-bran are not sufficient carbs).

In an upcoming blog, which I’ll call The Dukan Diet – My Thoughts (Part 2), I’ll explore why Dr Dukan sued another doctor for criticising his diet, and lost. I’ll also look into why the mainstream media is so obsessed with promoting commercial diet books. And I’ll suggest my own crazy commercial diet. Not that I’m saying the Dukan Diet is crazy.