Foie Gras is served at a restaurant in Bordeaux, France, March 31, 2006.

PARIS  - The French are becoming bigger and fatter and French women in particular are increasingly giving up on their renowned "taille fine," a survey that tracks weight patterns in France shows.

Nearly 42 percent of the French population older than 15 years has a weight problem, an ObEpi-Roche survey showed on Tuesday. Almost a third is overweight and 12.4 percent is obese.

Despite a notion that the French shun overeating and junk food, obesity is still on the rise, according to the study, which has been conducted every three years since 1997.

The closely watched survey is sponsored by drugs group Roche, which makes weight loss products, but it also mirrors growing concern in France on obesity and reflects other surveys which have shown trends such as rising average clothes sizes.

While the problem in France is not as serious as in countries such as the United States and the pace of growth has slowed compared with previous surveys, the data showed a steady rise in severe obesity that requires medical care.

"There is a small hope that a favorable trend is starting," Marie Aline Charles, head of research at the National Institute of health and medical research (INSERM) said.

"But you cannot state that we might begin to reverse this trend in France until other studies confirm our results."

Three years ago 11.3 percent of the adult population in France was obese against 8.2 percent in 1997, while the share of the population which is overweight has remained unchanged.

People are called overweight when their body mass index (BMI) -- weight divided by height -- is 25 or more and are obese when it exceeds 30. Severe obesity begins at 35, according to World Health Organization (WHO) standards.

"More than anything else, obesity is a health problem," Anne-Sophie Joly, head of French obesity lobby group CNAO told Reuters. "If you don't inform people they won't know."

Survey sponsors Roche produces a weight loss drug known as Xenical. Others include Sanofi-Aventis's Acomplia and Abott Laboratories's Meridia.

Campaigns were launched in France last year warning of the health dangers linked to obesity and by the end of this year the CNAO hopes to highlight a growing number of obese children.

Obesity is linked to income, the study showed. The highest percentage of obese people, nearly 19 percent, earn less than 900 euros ($1,139) a month. For the first time since 1997, however, obesity has diminished among those earning over 5,300 euros.

A separate TNS Worldpanel survey last week showed French households are spending 3 euros more on average -- or 132 euros in total -- on health products such as yoghurts and cereals that promise weight loss and lower cholesterol, in 2006 than in 2005.

TNS in an earlier survey said that extra-large clothes sizes accounted for 22 percent of French women's clothing sales at the beginning of this year compared with 18 percent in 2004. The percentage of women buying bigger C-cup bras rose 7 percentage points to 56 percent between 2000 and 2005, it showed.