...for tomorrow thinness may be out of vogue. While modern societies see fatness as undesirable, many past cultures considered it a virtue. What drives our attitudes? asks Felipe Fern¨¢ndez-Armesto

In the silly season a couple of years ago The New York Times ran a piece on a curious diplomatic incident in the Middle East. President Hosny Mubarak of Egypt had sent a special envoy to Prime Minister Ariel Sharon of Israel, who, instead of the sumptuous banquet the envoy expected, took him home for a meal and offered him "two sausages and a tomato".

President Mubarak responded to the insult by calling the offending host "a fatso". Mr Sharon promised that, if the envoy returned, he would lay on a third sausage.

The implications for the peace process were intriguing; fascinating light was shed on the perils of diplomacy. But I found myself wondering about a deeper historical issue: when was a leader first denounced for being fat? How and why do different cultures at different times respond to distended body shapes?

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The earliest traceable case of a politically maligned "fatso" comes, like President Mubarak, from Egypt. On the walls of the mortuary temple of the female pharaoh, Queen Hatshepsut, probably from the 15th century BC, there are images of the people of the Land of Punt, Egypt's distant and mysterious trading partner beyond the Red Sea.

Punt supplied rare aromatics that Egypt bought with massive consignments of food. The Punt folk appear as inferior and amusing. Their queen is depicted as grotesquely bulbous, with rolls of fat bulging over her body and surplus flesh overflowing her joints. To emphasise her obesity, the artist puts her in a diaphanous garment. The image may be realistic, but the emphasis clearly comes charged with disapproval. Hatshepsut herself was thin. We can be sure of that because distaste for fatness was one of the constant features of ancient Egyptian culture, which favoured a lean, columnar bodily aesthetic.

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In that respect, the ancient Egyptians were like us - and exceptionally so.

Fatness, in most cultures, has been highly esteemed. It was part of the earliest aesthetic known to us, embodied in paleolithic carvings, more than 20,000 years old, of triumphantly fat women.

For most of the rest of history, monstrous appetites were like other forms of heroism: qualifications for power. In early agrarian societies, kings were responsible for garnering food: it was reassuring for the people to see that their leaders were well fed. Where food was precious, only elites could get it in excess. This helped to make fat attractive.

Most cultures have fat icons of sexual potency to this day. But they are not always gendered in uniformly predictable ways. Big-hipped belly dancers are favoured by Middle Eastern aesthetics. In Japan, sumo wrestlers are much sought after as sexual partners. Among the Banyankole of East Africa, a girl prepares for marriage at about eight years old by staying indoors and drinking milk for a year until corpulence reduces her walk to a waddle.

Even in the West, it remained possible to think of fat as beautiful, without moral equivocation, until the late 19th century. The last images in the tradition are probably Renoir's charming, utterly innocent baigneuses .

Our present distaste for fat bodies runs counter not only to most of history but also - it seems - to evolution. The evidence lies in the comparisons we like to make between ourselves and other animals. We agonise about what, if anything, makes humans different.

One answer - and one we are generally reluctant to give - is that we are exceptionally fat animals. The biologist Caroline Pond has pointed out that an average middle-aged modern Western woman, with a body-mass index well short of overweight, has relatively more adipose tissue in her body by weight than a penguin or a polar bear. No other animal secretes so much fat, proportionately, in so many areas of the body as humans. We do not know the evolutionary reason for this - but presumably there must be one.

Certainly our egregious self-fattening has been a distinguishing feature of our species for millennia.

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Yet now we excoriate fat. We associate it with vice. We condemn its admirers as fetishists. We hound it out of office: Bill Clinton got into as much trouble for his slack waistline as his loose morals; yet as recently as the Twenties, America could have a president such as William H. Taft, who was so monumentally fat that he could not see his own feet nor tie his own shoelaces.

How did we get to this state? In the existing literature, five explanations are on the table.

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The first is the argument from progress. We have changed our mind about fat, say proponents of this explanation, because medical science has taught us to fear it. Historically, however, the aesthetic of thinness came first: medical opinions adjusted to follow it. Moreover, the odd thing about fatness is not that it sometimes undermines health but that fat people are usually salubrious and sometimes sprightly. In any case, our mythic convictions about the unhealthiness of fat overlook mental health. By comparison with the rest of history, we are in pretty good physical shape.

It is psychosis and neurosis that threatens to engulf us. Fat people, by universal acknowledgement, have fewer mental health problems than thin people.

A second possible explanation of our hostility to fat is that it is the result of the accumulation of tradition since the Renaissance: stoic and Christian bias to the thin have led to accelerating anxiety about the moral effects of overeating. But this cannot be a sufficient explanation on its own. We also need to know why some traditions prevail over others and why, as tradition accumulates, a critical threshold is reached at a particular time.

A third common explanation blames capitalism. The fashion industry and the diet industry have sold thinness to us, like any other commodity. But, in part, they were responding to demand from the public they served when they peddled anti-fat strategies and publicised thin body shapes.

The fourth explanation blames patriarchy: men who like their women thin.

But anecdotal evidence and common experience combine to show that men find a great variety of female body shapes sexually appealing. Even if the thin aesthetic did originate in male tastes, it is clearly a development in which women, as fashion-house executives and fashion-page editors, have been complicit. Feminism may even have encouraged the thin aesthetic by sanctioning dieters' obsession with control, not only of their lives and social roles, but also of their bodies.

The final explanation on the table is Roland Barthe's. He thought the bias to the thin was all a matter of the alternations of fashion. We happen to be going through a phase where thin bodies are fashionable. But fashion is the rapid, short-term oscillation of taste, whereas the rhythms I have described are very slow. The fat aesthetic prevailed for thousands, scores of thousands of years. And the thin aesthetic has prevailed now at least for a hundred years. So our problem transcends the vagaries of fashion.

To understand why the attitudes to fat have developed unusual features in the modern West, we must enter what I call the body shape marketplace. Body shapes are like other commodities, regulated by supply and demand. In a society of abundance such as ours, where a fat body shape becomes accessible to poor people, the rich, pursuing their vocation for being different, abjure their entitlement to be fat. In all the literature about the global explosion of obesity, and the disproportionate corpulence of the poor, one simple factor tends to be overlooked: the current and recent cheapness of food. The rich flee from what is cheap in fear of being cheapened. That is why in our society you cannot be too rich or too thin.

Once the rich adopted an aesthetic of thinness it was bound to dominate society.

Formerly, the rich were fat, the poor were lean. Nowadays, we have inverted historical normality: the poor are obese, the rich lissom. The poor buy cheap energy from the junk-food industry; the rich buy health foods and gym subscriptions.

So where do we go from here? I do not think on balance that we are likely to discard the thin aesthetic. The so-called global pandemic of obesity will inhibit us. Meanwhile, apologists for fat are waging an extremely unwise campaign, depicting fat people as victims: a persecuted minority that requires discriminatory legislation to escape the effects of prejudice. If you depict people as marginal, the probable effect will be to confirm their marginalisation: it is a self-fulfilling complaint. The best way to rehabilitate, and ultimately re-empower, fat people is to insist on the historic normality of fatness, and live with it in peace.

Felipe Fern¨¢ndez-Armesto is professor of global environmental history at Queen Mary, University of London, and author of So You Think You're Human , Oxford University Press, ?8.99.

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