ROUBAIX, France -- In a cold, stark municipal hall, 8-year-old Hatim sat silently as the pediatrician passed judgment.

At 4 feet 6 inches and 95 pounds, the boy was declared overweight and in danger of becoming obese.

The morning pastry would have to go. So would the soft drinks and the after-school Nutella-on-bread. Meat and potatoes would be allowed, but only once a day. A snack could include milk or cheese, but not both. Baguettes were fine, but where were the veggies?

Dr. Corinne Fassler, citing Hatim's 23.6 body mass index, said, "You have to raise your consciousness. You have to find a sport you like. But if you go to the swimming pool, don't go to the vending machine for chips."

The French are getting fatter, and Jan. 7 was National Weighing Day for the country's children. A voluntary army of hundreds of pediatricians fanned out to more than 80 cities to weigh, measure, interrogate and enlighten.

Roubaix is an economically depressed industrial town in northern France, the fattest region in the country. Fifty-one percent of the population here is overweight or obese, compared with the national average of 42 percent, according to the most recent national figures in 2003.

The trend line is most significant among children. While adult obesity is rising about 6 percent annually, among children the national rate of growth is 17 percent. At that rate, the French could be as fat as Americans by 2020. (More than 65 percent of the population in the United States is considered overweight or obese.)

In September, France banned soda-and-snack vending machines from public schools. The law also banned misleading TV and print food advertising and imposed a 1.5 percent tax on the advertising budgets of food companies that did not encourage healthy eating.

Schools have been urged to provide students with a half-hour of physical exercise a day. But the backlash from the food industry and a lack of political will has made it impossible to impose changes in advertising.

Some of the reasons for the increase in obesity are those that plague the United States and much of Europe: the lure of fast food and prepared foods, the ubiquity of unhealthy snacks and sedentary lives.

There also has been a breakdown in the classical French tradition of mealtime as a family ritual. In fact, the average French meal, which 25 years ago lasted 88 minutes, is just 38 minutes today.