Along with the latest must-have handbag or most popular TV programme we now have the diet of the moment – the Dukan, credited not only with the svelte silhouette of Carole Middleton but discussions in ladies' rooms all round the country. A high-protein diet devised by a Frenchman, it claims to mirror the healthy menu of early man, presumably excluding the mammoth's testicles, and has edged out the Atkins, which a few years ago half the women slimmers were on, trying to be on or had come off because they thought it made them smell like compost. Not to be confused with specialised medical diets: there are always several such on the go, and stalwarts such as WeightWatchers keep going – where else can you get a roomful of people to chorus "Well done, Mary!" simply by losing a few pounds? And desperate slimmers have weird personal diets. One friend won't eat anything white – presumably no potatoes, cream, baps and peppermints; though it does rather remind one of Davey's barmy diets in Nancy Mitford's Pursuit of Love – he ate only red things at one meal, white at the next. But even the dottiest diets can work, for the single thing that accounts for the success of even the looniest is that you are forced to be aware of everything you're eating. And, of course, drinking – but don't let's discuss that.