Are you permarexic?

We have become a nation obsessed with celebrity diets - supermodel Sophie Dahl decided super-slim was preferable to being voluptuous, actress Jennifer Aniston has tried the Atkins and Blood-Type diets while Sarah Ferguson is sponsored by WeightWatchers.

There are a higher proportion of overweight and underweight people in Britain than ever before, according to the independent market analysts Datamonitor. "Many underweight women are anorexic, but there's also a growing number of what we term as pathological dieters or permarexics: women who know they look fine and are determined to use any means to stay that way," says Laurence Gould from Datamonitor.

London nutritionist Ian Marber says: "Permarexics are unlikely to eat the five portions of fruit and vegetables a day which help protect against cancer and heart disease, and permanent dieting can lead to weakened bones, sleep problems, altered brain chemistry, feeling constantly cold and having irregular periods."

Symptoms include: