The International Herald Tribune reports that Parisian doctors are perplexed by the runaway success in the United States of the best-selling advice book “French Women Don’t Get Fat.”

“Oh, but they do!” said Dr. France Bellisle, a prominent obesity researcher here. “I work in a nutrition department where we see lots of people who are overweight. And I can tell you that French women are getting obese – and some massively obese – these days.”

In France, as in much of the world, the culprit is changing eating habits, experts said, as France’s powerful culture of traditional meals has given way to the pressures of modern life. The French now eat fewer formal meals than they did just a decade ago and they snack more.

The average Frech meal has decreased in length from an hour and 22 mintes in 1978 to just 38 minutes today.

Not surprisingly, food companies say that France is one of the most promising international markets for prepared items like frozen pizza, as well as for outlets like McDonald’s and Kentucky Fried Chicken, both of which are planning to open dozens of new stores in the country this year.