Low-carb meal. - File Photo.

PARIS: Pierre Dukan, the nutritionist behind the popular but controversial Dukan diet, has suggested that France tackle child obesity by giving extra exam marks for slimness.

Dukan, who has sold 8 million copies of his diet book worldwide, made the proposal in a 250-page book called 'An Open Letter to the Future President', which he sent out on Tuesday to 16 candidates for France's presidential election.

The plan calls for high school students to be allowed to take a so-called “ideal weight” option in their final year exams, the “baccalaureat”, under which they would earn extra points if they kept a body mass index (BMI) of between 18 and 25.

Those already overweight at the start of the two-year course would score double points if they managed to slim down over a period of two years.

“It's a fantastic motivator,” Dukan told Reuters.

“The baccalaureat is really important in France. Kids want to get it; their parents want them to even more, so why not get them to work together on nutrition?”

Weight gain is becoming an increasing problem in France and experts say sedentary lifestyles and poor nutrition are to blame.

World Health Organisation (WHO) figures show 50.7 per cent of the population was overweight in 2010, including 18.2 per cent classed as obese.

“There's a real problem. Since the 1960s the number of overweight people in France has risen from 500,000 to 22 million and it's going up every year,” Dukan said.

“When you reach those levels, it's no longer a health problem, it becomes a political problem, and the leaders of the nation need to worry about it.”

As well as the suggestion for students, Dukan's book, which will hit French bookshops on Thursday, contains a further 119 suggestions for the future president on ways to fight obesity.

One idea is the creation of a French fast-food restaurant serving more nutritional versions of the ubiquitous burgers and fries.

Dukan has earned an international reputation as diet guru to the stars, although his methods have drawn criticism from some health experts and weightwatchers who say his high-protein meal plan causes fatigue, bad breath and dizziness.

But he is also a committed campaigner for the promotion of healthier lifestyles.

He recently met executives from McDonald's France with a suggestion for a healthy “McDukan” burger, made with low-fat meat and with oatmeal bread instead of the usual white bun. Unfortunately, the giant food chain turned him down.

“They were interested, but they said the public wasn't quite ready for it yet,” he said.

The BMI, obtained by dividing a person's weight by the square of their height, is used as an indicator of the proportion of body fat. The WHO defines a BMI of 18.5 to 25 as normal, 25 to 30 as overweight, and over 30 as obese.