Give slim kids extra marks says diet guru Dukan

In a book to be published on Thursday, Dukan suggests that students in their last two years of secondary school be awarded extra marks if they manage to maintain an acceptable Body Mass Index (BMI), a measure of body fat based on height and weight.

"Obesity is a real public health problem that is rarely, if at all, taken into account by politicians," Dukan told the newspaper Le Parisien ahead of the book's launch.

Dukan said his plan would be "a good way to raise awareness among teenagers of the need for a balanced diet."

He denied that it would punish overweight children, saying: "There is nothing wrong with educating children about nutrition. This will not make any difference for those who do not need to lose weight. It will motivate the rest."

The book is entitled "An Open Letter to the Future President" and is being released ahead of the presidential election in France in April.

France has taken a series of measures to try to curb what experts say is a growing problem of obesity, including the introduction on January 1 of a tax on sugary drinks.

This despite the fact that the country is the lowest-ranked European country in terms of obesity, with 12.7 percent of women and 11.7 percent of men considered obese, according to a study released by the European Union's statistics agency in November.

The top rankings went to British women, of whom 23.9 percent are considered obese, and Maltese men, (24.7 percent).

Dukan has sold millions of books promoting his high-protein diet and many celebrities claim to follow his advice.