The sad truth is that in France it has been going poire-shaped for a while. I may have written a book (Two Lipsticks and a Lover) about how perfect French women are, but the kind of slim, well-manicured French woman that I wrote about is only found in Paris. The (very thin) former Chanel muse and supermodel Inès de la Fressange has also noticed a change in recent years: “French women don’t exercise. They are less obsessed by their figure, too. Maybe there is more wisdom now: they know health, children and love are more important. So in the country of fashion, women show less interest in their appearance.”

In my area of southern France, near Montpellier, I am actually among the thinner women. And, rather astonishingly, better dressed than most. I was also among the healthier eaters. I remember being utterly shocked at the junk that my children’s friends would be given to take to school as a snack, such as those terrible cheese strings and bits of processed ham.

On Thursday nights in our village, a man selling pizzas from his van would set up shop in the square. I used to buy a margherita, then cover it with rocket to make it healthier and tastier. That was if I could get through the crowds of Frenchies ordering their salami-strewn delicacies by the dozen. In fact, every new shop that opened in P?zenas was either an estate agent or a fast-food outlet. Everything from kebab shops to pizza-slice booths to deep-fried chicken. There is one particularly nasty fast-food chain called Quick, where the food is as unpalatable as the decor and the clientele are so enormous that they could have been flown in from Texas.

There are still Frenchwomen who subsist on a lettuce leaf a week, but they are in the minority. One reason could be that what is desirable has changed. As de la Fressange says: “Today being sexy seems to be an obsession, and very often sexy is the opposite of a bony girl.”

“It is about freedom of choice,” says my friend Sophie, a 44-year-old from Paris who weighs 59kg, so is not fat but jealously guards her right to be so. “We French women are very protective of our right to choose; our right to choose lovers, our careers and what and how much we eat.”

But surely they mind if they get fat? “Yes, of course, no one wants to get fat,” says Claire, a 50-year-old management consultant friend who lives in London but comes from Toulouse. “At least, I don’t. I suppose the women that do get fat don’t care about the way they look as much as we did. I think it is a younger generation thing, this letting yourself go. But I don’t think it will ever get as bad as it is in the UK.”

Helena Frith Powell’s first novel set in France, Love in a Warm Climate, will be published in September