BOOK REVIEW / No meat, high moral fibre: The Heretic's Feast: A History of Vegetarianism - Colin Spencer: 4th Estate, pounds 20

THE EARLIEST recorded jokes at the expense of vegetarians appear to date from the fourth and third centuries BC, according to Colin Spencer in this meticulously researched book. The followers of Pythagoras and his doctrine of asceticism inspired Antiphanes and Alexis and other Greek writers of comedy to much sarcastic banter about their strange dietary habits. Alexis, in Men of Tarentum, observed that the Pythagoreans 'are the only ones who drink no wine'. There are people today who believe that vegetarianism is synonymous with teetotalism. Some myths never seem to vanish.

The Heretic's Feast begins in pre-history and ends in the present day. We were all vegans once, in that distant time when we hunted solely for berries and edible grasses. It was only with the taming and domestication of animals that meat-eating became the norm in certain civilised societies: 'A captive animal was already half-tamed and its mystery, an inherent spur to mysticism, had disappeared. Animals, once domesticated, were not seen as animals, but were investment, wealth, sustenance and survival, part of the human struggle to exist.' They were sacrificed on altars, too.

Pythagoras is the first of the distinguished vegetarians Spencer describes at length. He recounts how the great philosopher and mathematician stopped a man beating a dog 'because he recognised in the dog's cries the voice of an old friend'. He saw no justification for inflicting violence on animals, and found no reason for eating their flesh. It was possible to survive on foods which resembled the aromatic spices the gods were said to live on: 'The more insubstantial the foods, the more the body was purified and the closer it could come to the gods, and to this end mallow and asphodel were an important part of the Pythagorean diet.'

Porphyry, Pythagoras's biographer, states that his subject also ate honey, millet, barley bread and either raw or cooked vegetables. Porphyry also says that Pythagoras was 'slim, lithe and energetic throughout his long life'.

He didn't eat beans, though. Pliny thought that Pythagoras believed the souls of the dead dwelt in them. The fava bean, Spencer tells us in one of his rare moments of eccentricity, resembles the female pudenda if 'squinted at sideways', and it was the bean's likeness to a vagina in shape that caused Pythagoras and his devotees to associate it with the sacred act of creation. Flatulence did not concern them.

From Pythagoras onwards, one gathers from Spencer's text, vegetarians have been more concerned with the state of their health and the strength of their convictions than with anything as mundane as pleasure. The word 'feast' is in the title, but there is little of feasting in the book itself. Sir Thomas More and Leonardo da Vinci lived by principles (the painter's louche aspects are not accounted for) and Bernard Shaw's attitudes to eating were unpleasantly priggish. Food, in his view, was simply another necessity for survival: it wasn't to be savoured or enjoyed. Adolf Hitler, the unloveliest of the famous vegetarians Spencer parades for our edification, had the most revolting taste of the lot. He loved gooey pastries to excess. I can't see what significance can be read into his near-incestuous sexual desires, but Spencer mentions them anyway.

At the close of The Heretic's Feast, Spencer reminds his readers of the horrors of factory-farming and the illnesses that the consumption of red meat brings in its wake. And still he does not talk of the pleasures of vegetarianism - how one can eat and drink and have a sex-life that isn't dependent on steak. When Walter and Jenny Fliese, refugees from Hitler's Germany, published their pioneering Modern Vegetarian Cooking some years ago, they felt it necessary to include recipes for nut cutlets and other dishes that looked like rissoles or roasts. Things have changed for the better since then, most notably with the appearance of Deborah Madison and Edward Espe Brown's superb The Greens Cook Book in 1987. The cuisines of India, Italy and the Middle East contain wonders to confound Shaw and Edward Carpenter and the oddballs who see divinity in a raw carrot.

Only the prospect of delight is absent from The Heretic's Feast - a book I shall keep as a storehouse of interesting and esoteric information, to dip into for what it has to tell me of the Essenes and the Manicheans and the Bogomils and all the other sects and individuals who felt that eating animals, fish and fowl is wrong.