Weight is clearly a growing problem for men, with 58 per cent of males overweight compared with 46.8 per cent of females. Male obesity is increasing by 1.8 per cent a year compared with a female rise of only 0.5%. Between five and eight per cent of WeightWatchers' half a million members are men - the figures would probably be a great deal higher if the club was geared less exclusively towards women. In one of its recent surveys, the club found that men were far more preoccupied with the size of their stomach than women (70 per cent compared with 43 per cent).
According to Susan Jebb, head of obesity research at Cambridge's Dunn Nutrition Centre, men and women also display different approaches to losing weight. "The commercial weight-loss market has had an impact on women but men feel it's not their sort of thing. They feel that exercise is more acceptable than eating less."
Where they pile on the pounds also differs from women. Jebb explains, "Men become apple- shaped whereas women grow pear-shaped. Men also tend to deposit fat over the abdomen, which is associated with a greater health risk. Women put it on subcutaneously, and over the hips and thighs. We know an element of it is hormonal, because after menopause women tend to put on weight more like men - around their stomachs."
What's slightly irksome is that dieting may actually be something men are quite good at, even though women have been doing it for many more years. "Anecdotally, men are often more successful at losing weight than women," says Jebb. "They do it less often but put their mind to it in a way that women don't."
Men are also more willing to discuss their anxieties about weight and now feel less ashamed about admitting to an interest in their appearance. As Phil Hilton, editor of Men's Health says, "They're far more conscious about their bodies than they used to be. The `I-don't-care' attitude has gone. Women aren't taking it."
Add to this the ever-looming crisis in masculinity and it's not hard to see how Slimmer's World For Men maybe just around the corner.
John, 30 and a writer, has successfully kept off the two or so stone he put on last year after he gave up smoking. "I was always tall and skinny but suddenly for the first time in my life I had a belly and a double chin. I tried various strategies, including smoking again." In the end he devised his own diet. "I relied on pre-prepared carrot batons and grapes - I'd carry them around with me and eat them every time I felt hungry or wanted a cigarette."
Jason, 32 and a freelance designer, has also entered the once-exclusive female world of calorie counting. "I don't feel dissatisfied with myself but obviously there is an element of looking at pictures of men with flat stomachs and then comparing yourself to them."
It sounds like a WeightWatchers confessional, but just goes to show that symptoms such as snacking, yo-yo dieting and an obsessive relationship with the bathroom scales aren't innately female preoccupations. It's more a matter of conditioning and social climate.
All the same, it's quite strange for women to be casual observers in all this. "It's amusing to see him checking all the labels in Sainsbury's for fat content," says Fiona, 28, a publishing assistant and Jason's girlfriend. "He can be a bit self-righteous about it sometimes. He only ever has fruit after his meals and I'll often have a dessert. Somehow, he always manages to make me feel like a real pig. I want to say, `Going on a diet is your problem.' I find it hard to be that sympathetic - I just start laughing when I see him checking out his love handles in the mirror. He gets quite hurt and says he's only doing it for me."
Perhaps that's because women refuse to take the whole issue too seriously. Why on earth should they when it's still obvious that men can be chubby and considered attractive in a way that women simply can't? Robbie Williams, Sean Ryder, Alexander McQueen and Paul Merton are just a few examples. Jo Brand hardly redresses the balance.
But there's also a sense that if women are prepared to put in the work to maintain their figures, then why shouldn't men? Moira, 33 and a teacher, says of her calorie-conscious fiancee Paul, also a teacher, "When I noticed his beer belly I did give him a hard time about it, in a jokey way, but only because I knew he'd be the same with me. He knows I prefer him when he looks slim."
Mick Cooper, psychologist and author of The MANual; The Complete Man's Guide To Life, says such an attitude is part of the reason why men now have no choice but to worry about their weight. "Nearly all the men I know have been on diets," he says. "These days women are more choosy. There's more pressure on men to be a 'good deal', to be good-looking and sexy. They can't get away with being tubby any longer."
As Moira says, "Paul would be the first one to tell me it I was letting go and he'd expect me to do something about it. It's only fair that he should make the effort too."