Be it milk, fizzy drinks or fast food, supermodels are the all-consumin g icons, says Marion Hume
In the United States it has been dubbed "The other Coke ad". Cindy Crawford has put her name to Pepsi, while Linda Evangelista has put hers to Coca-Cola. Now Naomi Campbell and Christie Brinkley have lent their faces and figures, free of charge, t o an American campaign aimed at encouraging youngsters to drink milk (as have Nastassja Kinski and Lauren Bacall).

The only snag is that these "Supers" are shown sporting milk moustaches. The joke going around New York City is that they look as if they have had a close encounter with the kind of coke that comes in powder form.

How preposterous! These poor women give up fees usually cited as "$10,000 a day" to pose for nothing in the hope that American youth will acquire some healthy eating habits. And all they get in return are fashion trade in-jokes. Of course, these have really been provoked by sheer surprise that slender Supers consume food at all. For the combination of supermodelling and eating does not sit together happily in the public imagination. Denial, slimming, lives of vitamin pills and bottles of mineral water are rather easier for the rest of us to believe.

Then there is Naomi Campbell's yoghurt ad. It hasn't yet been screened on British television (the first showing will be on Monday at 10.40pm in the commercial break of NYPD Blue), but the ad agency that hired Naomi to replace Joanna Lumley groaned at ourenquiry. It was clearly amazed that the anticipation of Ms Campbell spooning smooth Muller yoghurt (nine flavours, 108 calories each) between those bee-stung lips has caused such a string of tabloid stories this week.

But Naomi is hardly the first. Jean Shrimpton once implored the nation to "Use your loaf" in adverts that explained how she stayed slim by eating plenty of bread while "cutting down on the overall amount of food [she ate] and going easy on fried things".

More recently Kate Moss has done a milk ad ("98.4% Fat-Free. Not Her, The Milk"); while Elle "The Body" McPherson has advertised fast food. Hard to imagine she-of-the-washboard-stomach advertising Kentucky Fried Chicken, but she did. And, in the first place, The Body's springboard to supermodel was an ad: when she walked out of the Australian surf in a red bikini, clutching a can of a fizzy drink called Tab.

Fellow antipodean Rachel Hunter is keen to stress that she eats and drinks. She will star in a worldwide campaign for Budweiser this summer and will promote the opening of a chain of Outback restaurants in the US this year.

Allegedly, Christy Turlington was recently approached by a company that sells cooked ham to become their "face" (she declined). She has put her face and figure to the promotion of Special K breakfast cereal instead. Cindy Crawford is promoting Barilla pasta in Italy, as is former model turned super-actress Sharon Stone.

Meanwhile Nadege, a model popular in France, has advertised Mars bars - although her hand-span waist suggests either a mighty speedy metabolism or that she doesn't eat very many. And if the British model Lorraine Pascale consumes Haagen-Dazs with the abandon suggested by her ad, she must have a dynamic metabolism. Previous model food ads include Marie Helvin promoting fruit and vegetables (understandable); and Jerry Hall dressed up as a chicken for Bovril (rather harder to comprehend).

What models really eat will be revealed when the Fashion Cafe (think Planet Hollywood, but with Naomi, Elle and Claudia Schiffer, aka the Fanta model, instead of Arnie, Sly and Bruce Willis) opens in New York on 7 April. It is already provoking quips about plates of bean sprouts and rice cakes. But speculation about the Naomi burger, the Elle deli plate, the Claudia schnitzel is all denied by the restaurant's managers.

"We have grilled entrees, assorted pastas, seasonal salads and gourmet thin-crust pizzas, as well as pressed homemade focaccia sandwiches. We may feature the favourite dishes from the [trio's] home countries: England, Germany and Australia," said a spokesperson for the Fashion Cafe, which will have its first site in the Rockefeller Center Plaza. There is ample advance information on the launch party, the decor, the fashion artefacts collected, seasonal exhibits - including a bridal display featuring Valentino's wedding dress for Elizabeth Taylor - but no mention of Naomi burgers.