The popular Dukan diet has been slammed as “ineffective and without scientific basis”, The Daily Telegraph has today reported. The newspaper says that the British Dietetic Association has criticised a range of celebrity diets, including the Dukan diet rumoured to be used by Kate Middleton.
Anticipating the huge surge in dieting around Christmas and New Year, the association has drawn up a list of five 'fad diets' that slimmers may be considering after reading about celebrities using them to stay trim. According to the British Dietetic Association (BDA), the top diets to avoid are:
Sian Porter, consultant dietitian and spokesperson for the BDA says, ‘Sadly, there is no magic wand you can wave. If you have some weight you need to lose, then do it in a healthy, enjoyable and sustainable way. In the long term this will achieve the results you are after.’
Among the diets chosen by the BDA, the Dukan diet stands out as the most popular, with millions of people around the world having tried it in recent years. In particular, the interest has grown even further since newspapers reported that Kate and Pippa Middleton may have used the diet to slim down before the royal wedding.
However, while the diet is hugely popular it has come under some serious criticism from organisations such as the BDA. In addition to their damning conclusion that there is ‘absolutely no solid science behind this at all’, a respected French health publication has said they could not find any scientific reports that supported a long-term impact from the diet.
Unable to find this evidence, Le Journal des Femmes Sante surveyed followers of the diet and found that despite rapidly losing weight in the initial, restrictive phases of the diet, the vast majority regained all the weight they had lost within the next few years.
In addition, given the rise of restrictive diets such as the Dukan plan, the French Agency for Food, Environmental and Occupational Health and Safety reportedly published warnings against the nutritional deficiencies that restrictive diets might cause. The agency also highlighted the potential long-term effects of these restrictive diets, especially the tendency for most restrictive dieters to regain the weight they had lost.
While many Dukan diet users have reported impressive weight loss results in the initial phases of the diet, many organisations feel there is a lack of solid scientific evidence on whether the Dukan diet is sustainable and effective in the long term.
While survey results must be approached cautiously, as they are less robust than scientific studies, the results gathered by Le Journal des Femmes Sante give perhaps the best indication to date on whether the Dukan diet actually produces lasting results. Based on the survey of nearly 5,000 Dukan dieters:
The study's authors say, 'These results explain why people give positive feedback when interviewed during the first year. They also confirm that in the medium and long term, the Dukan diet is no more efficient than any of the other restrictive diets.
'When the diet fails, the weight regain accelerates after six months. For 50% of respondents it occurs most of the time between six months and two years after the start of the diet.'
The authors of the report say that these results are consistent those from a 2009 survey on restrictive diets conducted by the French health authorities.
Again, the reported lack of long-term research means it is difficult to tell, but the report offers some insight from both dieters and medical experts.
The stabilisation phase
Around two-thirds of people that failed to complete the diet said they did not get through the 'stabilisation phase' of the diet, the fourth and final stage in the regime. It includes features such as a dedicated protein day and the inclusion of simple exercises. Some detractors of the diet have said that it is too hard to follow and that adjusting to this phase is too difficult.
The yo-yo effect
The report also featured the opinions of a panel of doctors and dietitians, who were generally critical of the Dukan diet and the effect it can have on the body. In particular, they say that the restrictive diet changes the body's metabolism (the way the body stores and uses energy), which can lead to a yo-yo effect, where dieters constantly lose and regain weight.
Dr Marie-Josée Leblanc says, ‘It’s very uncommon for this type of diet to remain efficient in the medium run. By imposing such an abrupt decrease in the energy supplied to the body, you force it to adapt and it learns to function on fewer calories. As a result, when you revert to a normal diet again, your body receives way too many calories in comparison to what it needs. It will then start to store this energy as fat. It’s the so-called yo-yo effect.’
The psychological effect
Professor Monique Romon argues that the initial success seen with many diets such as the Dukan plan is that they can lead to negative feelings once weight loss starts to slow down: 'Most of the time, overweight or obese people start a diet in order to reach an ideal weight they’ve always dreamed of. But in every diet, there are steps in the weight loss, with plateaus that are normal. As soon as they think it doesn’t work anymore, their motivation decreases and they develop a feeling of guilt and they think they won’t be able to make it. Therefore, they stop the diet, then start another one, then stop, etc.'
The lack of long-term research makes it hard to tell but the authors of the report stress the possibility that restrictive diets can cause nutrient deficiencies, diabetes, cardiovascular disease and bowel problems. They say that restrictive diets:
There are a number of well-researched weight loss methods that tend to focus on developing a slower, sustainable way of losing weight than can also be kept off in the future. They tend to involve eating sensibly and exercising rather than rapid weight loss and drastic rules denying you from eating what you want. Some methods include:
For other weight loss ideas try our section on dieting tips and real-life weight loss stories.