Oh, it was delicious. The deep savouriness of the crabmeat, combined with the honeyed tang of the vinegar and the arresting sharpness of the ginger, made a sublime chord of flavour. I demolished the rest of the legs. I sighed. Finally, I began to lap up the custard-like meat inside the shell, nature's foie gras, and the yolk-yellow semen, dripping with golden oil. Outside the window, the sun gleamed on the still, blue waters of the lake.

My steamed crab crouched on the table in front of me in a blaze of sunset-orange, its claws bearded with moss-like fur, its legs fringed with spiky yellow hair. It looked as though it might scuttle away at any moment. I prepared for the attack. Eating hairy crabs is a messy business. You cannot avoid a tussle with shell and flesh: crunch, suck, crack, lick, probe, slurp. The restaurant had provided an array of stainless-steel tools, along with dry napkins, wet napkins, plastic gloves and toothpicks. So I crushed the legs with the crushers and poked out their tender meat, excavated the frondy white flesh of the claws. Then I dipped the meat into a saucer of ginger-infused vinegar before popping it into my mouth.

Many Chinese people are obsessed with crabs, yet no one has ever managed to match the crab-induced ecstasies of the seventeenth-century play wright Li Yu. 'As regards the excellence of food and drink,' he wrote, 'there is not one single thing whose exquisiteness I am unable to describe… And yet when it comes to crabs, while my heart lusts after them and my mouth enjoys their delectable taste (and in my whole life there has not been a single day when I have forgotten them), I can't even begin to describe or make clear why I love them, why I adore their sweet taste, and why I can never forget them…'I have lusted after crabs all my life,' he went on, 'to the extent that every year as the crab season approaches, I save up my money in anticipation. My family tease me so much for treating crabs as though my life depends on them that I think I may as well call these savings my "ransom money". From the first day of the crab season until the last day they are sold, I… do not let a single evening pass without eating them. All my friends know about my craving for crabs, and they entertain and fête me with them during the season; therefore I call the ninth and tenth months "crab autumn"… Dear crab, dear crab, you and I, are we to be lifelong companions?'

It wasn't surprising, I thought, that the pleasures of crab had been one of the themes of Chinese life and literature for centuries. Every autumn, at the start of the crab season, gourmets from Hong Kong, Tokyo and even further afield flocked to eastern China to eat them. It was a seasonal event, like the Grand National in England, or the Monaco Grand Prix. The female crabs ripen in the ninth lunar month, followed quickly by the males, and from then until the year's end it's a non-stop orgy of crabbery. Chefs in fancy restaurants incorporate hairy crab into extravagant recipes: stewed turtle with crabmeat, silken beancurd with crabmeat, 'soup' dumplings stuffed with pork and crab… Ephemeral crab shops spring up on the streets, selling live crabs burbling away in tubs, panes of glass to stop them running away.

The centre of the autumn crab trade is the lakeside city of Kunshan in greater Suzhou, but these days it's a nightmare of commercial tourism. Coaches disgorge their parties of proles at tacky restaurants, where they gorge on crabs and have their photographs taken. Someone as cosmopolitan as Li Jing wouldn't dream of going to a place like that. Instead, we turned off the main road and drove through fields of cabbages to a restaurant perched on an unspoilt stretch of the lake's shore. We left the jeep and pattered over a zig-zag of bamboo walkways to a dining room propped up on stilts in the shallows.

The best crabs in China, everyone agrees, are those reared in the Yangcheng Lake near Suzhou, because of the limpid purity of its waters. That is why I ended up, on that warm October Sunday, making a day trip with friends to the shores of the lake. I was with Gwen, an old classmate from Sichuan University, and our ringleader was Li Jing, a glamorous Shanghainese divorcée in her thirties to whom Gwen had introduced me. The Shanghainese are notoriously snooty and rarely associate with the Westerners who now reside in their city. But Li Jing had lived in France, spoke fluent French and English, and worked for an international company. She was unusually open-minded, and she loved to eat. So she persuaded a rich and well-connected friend to drive us out of Shanghai in his jeep, along the new crab expressway towards Suzhou.

As I savoured the last, tantalising morsels of meat in my crab, I glanced over at Li Jing. Dark hair falling about her shoulders, she was sucking at the coral-red ovaries of her own, female crab, her fingers shiny with its most intimate juices. Everyone in the dining room was locked in silent concentration, the only sounds the determined crunching of shells and a gentle, pervasive slurping. Once, our taciturn companion, the son of a Chinese admiral, aloof with his own self-importance, broke his silence to say, 'Remember that the crab is very cooling (han), you should drink some wine with it, otherwise you'll get a stomachache.' He nodded in the direction of the warm Shaoxing wine, infused with heating ginger. I took my wine cup in fingers stained yellow by crab semen, and raised it to my lips. The warm alcohol went straight to my head.

By the time we had finished our lunch, the trays on the table were piled with crab debris. We sat around for a while, drinking wine and chatting. 'This is one of the best hairy crab restaurants in the area,' said Li Jing. 'It may look plain, but the crab they serve here is a "green food product", not like the industrialised crabs you find in Kunshan. They are reared outside, just over there, on a diet of fish and snails rather than artificial feed. Even national leaders come here to eat.'

Soon after we visited the restaurant, a crab scandal blew up in the Chinese national press. Officials from the Taiwanese health ministry had examined a shipment of hairy crabs imported from the Yangcheng Lake, and found them to be contaminated with residues of an antibiotic that has been linked to cancer, AOZ. Yangcheng crab breeders insisted that they didn't use AOZ, and that the problem must lie with crabs from elsewhere that were being passed off as the real thing. According to the official Chinese media, local crab-eaters were undeterred by this cancerous little rumour, and blithely went on eating crabs for the rest of the season. But the story left a bad taste in my mouth. For the rest of my stay in Shanghai, I found myself avoiding hairy crab wherever possible.

Gwen and I left Li Jing and her friend at the table, and wandered out to look at the crab farm. Over the entrance, a large signboard showed a photograph of the former General Secretary of the Chinese Communist Party, Jiang Zemin, gazing into a basket of live crabs at the restaurant. Inside, the crabs lived in large cages suspended in an inlet of the lake. One of the crab-keepers showed us around, and pulled out a great hairy crab in his hand. He grinned as it waved its legs around in futile protest. What with the sun, the fresh air and the lightheadedness brought on by the wine, we were in a good mood. Until we noticed the state of the water. An oily scum swirled on the surface, with a mass of grubby flotsam that had drifted in from the lake. The legend of the pure Yangcheng waters, like so many others in China, had failed to keep pace with an industrialised reality. The thought of the crabs we had just eaten, raised amid such filth, was suddenly unappealing.

Three-quarters of the half-million or so food-processing plants in China are small and privately owned. For their owners, it's often cheaper to pay the occasional fine than to invest in safe production. Once I wheedled my way into an illegal factory making preserved duck eggs on the outskirts of Chengdu. It was a small, fly-by-night workshop in a filthy yard. The workers there told me that their eggs took a mere seven-to-ten days to mature rather than the traditional three months: a sure sign, said the friend who accompanied me, that they were 'fast' preserved eggs, speeded-up by additives like ammonia.

Every time I look in a Chinese newspaper these days, it is full of food scares. Ten years ago, such stories were few and far between, and those I did come across seemed almost comical -- like that of the Shanghai eel farmer who kept his eels on the human contraceptive pill to make them plumper. Now the tales are nastier, and they come thick and fast: 300 people in Shanghai poisoned by pork tainted by the drug clenbuterol; duck eggs doctored with an industrial dye; fifty babies killed by fake formula milk. It's partly, of course, because the Chinese newspapers are more frank than they used to be when in comes to discussing unpleasant issues. But it's also because of runaway economic growth, poor regulation and widespread corruption.

The Chinese government was so embarrassed by the global furore that it sprang into action. Officials announced a crackdown on small, poorly regulated food-processing firms, and conducted a nationwide inspection into food safety. The results were unsettling. Inspectors found illegal industrial materials such as dyes, mineral oils, paraffin wax, formaldehyde and malachite green used in the manufacture of all kinds of ordinary foods: flour, sweets, pickles, biscuits, dried fungi, melon seeds, beancurd and seafood. The scale of corruption in the food regulation system was made clear when the former head of the Chinese Food and Drug Administration was executed for taking bribes.

The contamination of Chinese food products hit the international headlines in the spring of 2007. Ironically it was concern at the health of animals, rather than people, that started it. When American cats and dogs started dying in odd circumstances, the cause was found to be a Chinese-made ingredient in their food: wheat gluten that had been doctored with the chemical melamine, a cheap protein-enhancer. The world started looking at Chinese imports with greater scrutiny. American journalists dredged up years-worth of US Food and Drug Administration reports documenting rejected imports from China: mushrooms laced with illegal pesticides; prunes stained with chemical dyes; shrimp tainted with carcinogenic antibacterials. The United States had turned back over a hundred shipments of Chinese food products in a single month that spring. And these were just the imports that had been intercepted.

So it's not just middle-class paranoia that has made some of my Chinese friends hesitant about eating meat in the last few years, and my Hong Kong friends wary of ingredients imported from Mainland China. My own enjoyment of eating in China has been clouded by growing anxiety about what's actually in the food on the table. Those tempting prawns, stir-fried with black beans and chilli; that sweet-and-sour carp… Fish farms in China seem to slip a lot of banned antibiotics and fungicides into their ponds, so these may well be tainted by residues. Those tender chunks of belly pork with jujubes… growth hormones, anyone? What about the questionable chemicals used in the manufacture of deep-fried doughsticks, or the lead oxide that is a traditional additive to preserved duck eggs? Most chickens now are battery farmed, almost certainly, in conditions that I'd rather not think about in England, let alone in China. Furthermore, I've watched those peasants with cans of pesticides on their backs, drenching their beans and cabbages.

Even before the pet-food scandal, a Chinese official who had once been responsible for controlling doping in sports, Yang Shumin, warned that athletes competing in the 2008 Beijing Olympics might fail their drugs tests if they dined out in restaurants, because so many anabolic steroids were routinely pumped into Chinese meat. In an attempt to avert panic in the sports world, the government hastily promised that all the food served in the Olympic Village would be purchased from selected suppliers, wrapped in tamper-proof packaging and delivered by tracked vehicles. Furthermore, the kitchens would be guarded round the clock, and all the ingredients used in cooking for the athletes would first be tested on mice! Their pledges were hardly reassuring for those of us living outside the sterile, armed-guarded, mouse-tested confines of the future Olympic Village.

In England I eat as much organic produce as possible, avoid factory-farmed meat and poultry, and steer clear of junk food, mostly. In China, such fastidiousness is impossible. What's a professional omnivore to do?

Aside from the deliberate adulteration of food by corrupt manufacturers, the pollution is so dire in many parts of China that it poses a direct and grave threat to human health. According to the government's own figures, 10 per cent of Chinese farmland is dangerously contaminated with excessive fertilisers, heavy metals and solid waste, and a third of the rural population lacks access to safe drinking water. Many rivers are so filthy that their waters are toxic in contact with human skin. The newspapers are filled with terrifying stories about poisoned lakes and reservoirs, their waters unfit even for irrigation. According to a World Bank report, which the Chinese government tried to suppress, 700,000 Chinese people die prematurely every year because of air and water pollution.

Anyone living in China knows that these are not just abstract statistics. If you go out on to the streets of Beijing on a bad day, you can sense the pollution as you inhale. You will probably choke on it. Often when I go back to Chengdu or Changsha these days, I develop a cough, a headache and an asthmatic wheeze. While I'm in China, I drink Chinese tea all the time, because I adore it. Once in a while, though, when I feel that I've had enough tea, I drink a mugful of bai kai shui, plain boiled water, instead. It's usually a shocking experience. In Hunan, one memorable mugful of bai kai shui tasted of petrol and God-knows-what other chemical effluents. Even when the taste is not so extreme, the water, unmasked by tealeaves, tends to have a metallic tinge. Often, I want to spit it out immediately -- but what's the point, when the same water is used to cook all the food I eat?

One day when I was living in Hunan, I went to visit a friend in Zhuzhou. Zhuzhou is on the World Bank list of the world's most polluted cities (China lays claim to sixteen of the top twenty on that list). It was a terrifying place, a blighted metropolis where the chimneys of the local metallurgy and chemical plants spewed their vile, gaseous excrement over the entire landscape. I waited for my friend in a taxi outside his work unit. The view through the car windows was apocalyptic, trails of white smoke shrouding everything, blotting out the sun. One chimney on a lower slope sent its filthy plume directly into the compound where he worked. The air was so foul that I, an outsider, scarcely dared breathe. I ate very little at lunch, because although the food was delicious, I was thinking of the tainted earth in which the vegetables must have sprouted, the corrupted water in which the fish had probably been farmed. I didn't want to let any of it into my body. How anyone could live there I did not know.

The world is currently deeply enamoured of China, and everyone wants to go there on holiday. Flick through any travel magazine and you'll very likely come across an article on the glamorous Shanghai restaurant scene, or perhaps, in the right season, on the delights of hairy crabs. But you don't see much mention of the country's terrible environmental problems. When I was in New York recently, I met up with another Chinese food writer who lived there. She had just returned from China, where she had been flabbergasted by the pollution. 'It's appalling,' she whispered to me. 'Why doesn't anyone talk about it?'

My ex-pat friends in Shanghai and Beijing, particularly those with small children, don't like to think too much about the food, air or water they are forced to ingest. They try to calm their fears by making small adjustments to their lifestyles: not eating at street stalls or more dubious restaurants, for example. Even in fine establishments, there there are certain things they avoid like the plague. Once, when lunching with my Italian friend Davide in our favourite Shanghai restaurant, I was tempted to order the slippery whitefish, a local speciality. Davide raised an eyebrow. 'Have you looked at the water recently?' he said. One top Shanghai chef, internationally renowned, confessed to me that the greatest challenge of working in China was trying to source decent ingredients.

Now, when I'm in China, I find I eat far less meat, fish and poultry that I used to, because I just don't trust them. Of course I want to eat everything, because the cooking is as fabulous as ever, and I'm as curious as I always have been about Chinese food. But can I face such a cocktail of hormones and chemicals? My fears are not greatly eased by headlines in the China Daily that say: 'Most vegetables safe: official'. The only foods I eat with complete confidence are the wild bamboo shoots, wild vegetables and farmhouse produce I encounter in remote rural areas.

It's as if my gastronomic libido is slipping away. In the old days, in Sichuan, my hunger was a free and joyful thing. The food before me was fresh, free-range and wholesome, and I wanted to devour it all. But in the last ten or fifteen years China has changed beyond all recognition. I've seen the sewer-like rivers, the suppurating sores of lakes. I've read the newspaper reports; breathed the toxic air and drunk the dirty water. And I've eaten far too much meat from endangered species. In China I have to throw all my principles to the wind if I am continue in my vow of eating everything. The only way to recover my wanton old appetites is to draw a deliberate blind over all the evidence, to switch off my brain, and to eat without thinking. And I'm not sure I can do it anymore.

Not long ago, I was back in Chengdu for a lightning visit, to research a couple of articles and catch up with friends. A businessman acquaintance had invited me out for dinner. Our taxi pulled into the driveway of a restaurant on the outskirts of town. A grubby red carpet ran up the wide steps from the street and across the vast empty lobby, stained by the filthy soles of thousands of greedily stampeding feet, rushing in from their taxis and company cars. Girls in red silken dresses stood in rows to welcome us; glittering chandeliers hung overhead. Inside, the restaurant was decorated in the newly fashionable 'European style', with padded, upholstered chairs that looked a bit French.

Although few Chinese people would eat like this at home, it was a typical restaurant dinner. 'Hen lang fei (very wasteful)!' said my host, with an embarrassed laugh. But he had ordered all that food himself, knowing that it was more than we could finish: his apologetic comment was made purely for my benefit, because he sensed that I, as a foreigner, might disapprove. We both knew that at this dinner hour, across the country, tables groaned like this with wasted food. In provincial capitals such as Chengdu and Changsha, there were super-restaurants that could seat five hundred, a thousand, two thousand, even four thousand guests simultaneously. And no one ever finished what was on the table. Even in remote county towns, I had witnessed scenes of such gargantuan excess that they could have been part of a medieval morality play.

The rest of the party was already assembled. I took my place at our table, in the main dining hall. None of us was really hungry, but someone was paying for the dinner on company expenses, and it doesn't look good in China to sit before a modest table. My friend therefore ordered a fanfare of scarlet prawns with an elaborate garnish; a whole fish, steamed; crabs smothered in chilli and garlic; a whole knuckle of pork; chicken, duck and beef in great quantities; expensive wild mushrooms; soups and dumplings. To me, it all seemed like vulgar food: garish to look at and taste; enhanced by food colourings, chicken powder and MSG. We toyed with it, but no one was really eating. Most of it would go into the pigswill in an hour or two.

In some ways, such decadence is perfectly understandable. Anybody over fifty in China lived through Mao's terrible famine and the ensuing decades of rationing. Not long ago, peasants rubbed pieces of pork fat around their woks to lend a hint of meaty flavour to their vegetables, before putting the fat carefully away so it could be used again. Some people have told me they actually had dreams about pork in the 1960s. In some ways, China is still living through an extreme reaction to those years of deprivation. The profligacy is part of a vast, collective sigh of relief that it's over, that there is meat on the table, and that the puritanical Mao failed to to stifle one of the greatest pleasures of Chinese life.

It is also cultural. The banquet in China is a social institution. If you are hosting a dinner for family members and friends, it's an expression of love and generosity. For clients and colleagues, it might be a demonstration of wealth and power, and a chance to win 'face' -- that peculiar Chinese concept that expresses a person's social and professional dignity. In either context, you must overwhelm your guests with food, the best you can offer. The best, of course, is almost always meat, fish and poultry rather than grains and vegetables. At a proper banquet, you may not be offered rice at all.

The Chinese are also afflicted increasingly with the diseases of plenty that are so familiar in the Western world: obesity, diabetes and cancer. Grandparents who once went hungry stuff their grandchildren with fast food and sweets. I've seen some of my middle-aged friends, dining out almost every night, become plump and pasty.

Many people frown on the traditional style of banqueting. The Chinese authorities, clearly troubled by visions of the nation's wealth squandered in a litter of half-eaten meals, issue occasional circulars urging moderation and banning the holding of banquets at public expense. And for businessmen, the endless round of feasts they must attend in the course of their work can be a torment, particularly because they usually involve forced bai jiu toasts and unavoidable drunkenness. One former colleague of mine, an Englishman working as a sales rep in Henan Province, became so sick in the course of his professional socialising that a Beijing doctor diagnosed him as suffering from 'banquet fever'.

When I eat in these flashy, extravagant restaurants, I find myself thinking nostalgically of my first year in Sichuan, when I was so moved by the frugality of the way people ate. I remember lunches of egg-fried rice livened up with morsels of meat, or a few simple vegetable stir-fries. I yearn also for the dishes that I lived on as a student, sitting on a stool in the Bamboo Bar and the other small restaurants around Sichuan University: the delicious fish-fragrant aubergines, the duck hearts with chilli, the stir-fried silk gourd, the twice-cooked pork with green garlic. Every so often I still find one of these mom-and-pop places, tucked away in a small street that has somehow escaped the demolition crews, serving unfashionably traditional dishes in a white-tiled shed with formica chairs and tables, and I think I'll be disappointed. But then the food arrives, and tastes as good as I remember, and it warms my heart. I forget, for a while, about the pollution and the hormones. And it reminds me why I fell in love with China, and why my first book about Sichuan cookery demanded to be written.

'Just think how many lives we are eating,' said Gwen, 'Ten thousand, twenty thousand?'

It was true. Each spoonful of soup was a confusion of dozens, perhaps hundreds, of small fishy lives.

'I feel so guilty,' said Gwen, sipping her soup. It was a Shanghainese soup -- a pale, slightly thickened broth filled with wisps of something that might have been tofu or eggwhite, but on closer inspection was a mass of tiny, thread-like fish. Each strandy creature had two black eyes on its pin-like head, about the size of specks of black pepper.

One evening, I was having dinner with Gwen in a Shanghai restaurant.

'Somehow it seems worse to eat so many,' said Gwen. 'Much worse than, say, eating a single eel.'

What she said made me shiver, and I, too, finished my soup with a feeling of guilt.

There's a nineteenth-century English engraving called 'Fatal effects of gluttony: A Lord Mayor's Day Nightmare'. Dedicated to 'all the city's gourmands', it depicts a fat London merchant lying in bed, suffering the consequences of his carnivorous self-indulgence. A swarm of animals lay siege to him in a terrifying hallucination: ducks, geese, cow, pig, stag, wild boar, sturgeon, flying fish, they besiege him within the curtains of his bed. A lobster tries to pinch his nose, and an enormous turtle straddles his chest.

As a scholarship student in Chengdu, I longed to taste the exotic foods that had graced the tables of emperors. Now, I feel a dawning revulsion. Is there anything a Chinese gourmand will not eat? Alligator flesh, the downy antlers of the young deer, rabbit's kidneys, the palms of chicken's feet, those orangutan lips… a riot of animals, pillaged for our titillation. Sometimes it seems beyond satire, as pretentious as the food served at Petronius' 'Banquet of Trimalchio'.

Sometimes, when I think of what I've eaten in China, I imagine that I'll end up like this. There's an entry in one of my 1999 notebooks that reads: 'In the last three days I have eaten: snails, frogs, snakes, sparrow gizzard, duck tongues, fish heads, duck hearts, tripe; also half a duck, most of a carp, duck's blood, at least five whole eggs, smoked bacon, and stewed aromatic beef.' I'm ashamed to say that this kind of excess is not unusual. A vegan friend of mine once told me that all the animals I'd eaten in the course of my life would sit in judgement over me after I was dead. 'Most people,' he said, 'would just have a row or two of judges: a cow and a pig, a sheep and a chicken. But you -- imagine, them, Fuchsia, they'd be like the audience in a football stadium, tier upon tier: civet cats, dogs, snakes, frogs, fat-tailed sheep, muntjac, eels, etc. etc.'

In the course of my duties as a professional food writer, I am offered such esoteric delicacies at every turn. Often the circumstances make it hard to refuse. A bowl of shark's fin soup placed before me by a generous host; the eyes of the other guests fixed on me expectantly, hoping that I am able to appreciate the honour. We all know that a single bowlful of shark's fin soup costs hundreds of yuan. I hesitate. Then, with a guilty conscience, I smile, sip, and praise it for its soft, strandy texture, the subtle savours of the broth.

The bronze ritual vessels of the Shang and Zhou dynasties are among the most ancient and potent symbols of Chinese civilisation. Wine jugs, cooking pots and steamers, they are decorated with geometric designs based on the stylised faces of monstrous animals with curled horns and staring eyes. You can see them in the oriental collections of most world-class museums. On some bronzes, the animals resemble tigers, bulls or birds; on others they are more abstract. No one knows exactly what these menacing beasts meant to the people of the Shang and Zhou, but they are known in China as tao tie. This word means, in modern Chinese parlance, 'a fierce and cruel person, or a glutton'; tao tie was also the name of an ancient villain known for his voracity, according to one antique text. The fierce animal designs of the sacrificial bronzes, one of the most recognisable symbols of Chinese civilisation, have for centuries been bound up with the idea of monstrous greed.

The influential archaeologist, K. C. Chang, in an essay on ancient Chinese food history, once suggested that those threatening animal designs may have been emblazoned on the ritual vessels used by the Shang and Zhou ruling classes as a reminder of the dangers of gluttony. Like the memento mori of medieval Europe -- those images of death that were intended to remind people of their mortality -- they may have been a warning to the 'meat-eaters' of their day that greed was monstrous and corrupting.

In recent years, as I eat in China, the shadow of the tao tie has seemed to loom more and more insistently over the dinner table. It makes me feel sick at heart. The banquets that once seemed to be a glorious perk of my job have begun to feel like an occupational hazard, a minefield of ethical, environmental and health issues. I find myself torn between my old habit of omnivorousness, and a moral loss of appetite. A horned tao tie beast watches me as I sip my shark's fin soup, staring at me with its ancient, beady eyes. I can no longer meet its gaze.

I feel a rising sense of panic. This is my life, my work, to eat in China. I have built a career on it. For more than a decade I have been a professional glutton. My cast-iron digestion has protected me from the immediate risks of eating everything, though I have been reckless in my omnivorousness. My intellectual fascination is undimmed. But I just can't do this anymore. The food-writer has lost her appetite.

My loss of appetite creeps up on me. I soldier on, attending feast after feast, but I'm actually eating less and less. A mulish resistance sits on my stomach. I taste things, pick at them, write my notes. And then I go home to wherever I am staying and fill up on instant noodles because they are the only food I can face. I feel a kind of kinship with that great Qing Dynasty gourmet Yuan Mei, who went home after a forty-course dinner party, appalled at its vulgar excesses, and needed a bowl of rice porridge to assuage his hunger. After each trip, I fly back to England with dull skin and drab hair, feeling rundown, and it takes me a few weeks to recover.

Of course I'm aware that, at some level, my distaste is also a metaphor. I'm weary not only of this constant feasting, but also of travelling, and of China. For years I have given everything to this country, and it's wearing me out. I'm tired of always being the perfect diplomat; I'm exhausted by the crazy, peripatetic lifestyle.

As I sit at these debauched Chinese dinner tables, I think of the looming food crisis of which scientists are warning. Climate change is beginning to damage food production; China and India are switching to meat-based diets that demand more land; water tables are falling; and the global population is rising. The era of cheap food and surpluses may be over. How mad this profligacy will seem, in the not-too-distant future, when we are fighting over oil and water, perhaps even grain. These banquets -- tables laden with fish and meat, platefuls of shrimp and chicken that end up in pigswill -- will seem like an hallucination, echoes of a few greedy, giddy decades sandwiched between periods of rationing and scarcity. Decades when we forgot the value of things.

There are pages of despair in my diaries, now, among the recipes and sketches.

I'm always missing someone, something. Now I've eaten my fill; I just want to go home. I don't want to spend my life consuming rabbitheads and sea cucumbers. I want to grow vegetables in my own garden, to cook shortbread and steak-and-kidney pie.

The tao tie beast, with its gluttonous associations, may be a symbol of Chinese civilisation, and the Chinese may do gluttony better than anyone, but I wonder, in the end, aren't we all just as bad? What's the difference, really, between eating shark's fin and caviar? Or cod, or bluefin tuna? They are all, now, endangered species. A third of the food bought by British households ends up being thrown in the bin. And look at us, flying around the world on holiday, eating beef reared on ranches that used to be rainforest, buying unseasonal produce flown in from the other side of the world. Think of the increasing amounts of land being given over to growing grain for ethanol production. If feeding your car on grain that could be used to nourish poor African farmers isn't the mark of the tao tie, I don't know what is.

The Chinese do seem to eat everything, one must admit. But in a sense they are just a distorting mirror, magnifying the voracity of the entire human race. The Chinese word for 'population' is 'people mouths', and in China there are now 1.3 billion mouths, all munching away. China itself is like a big mouth eating. And it is hungry for more than just Chinese ingredients. The Chinese are slurping up the seafood of the world's oceans. And now that they have discovered dairy products, they want our milk, too, to feed their children, and their growing appetite for it is inflating milk prices on global markets. It's the same with timber, mineral and oil, which feed Chinese economic development. China has become the world's largest consumer of grain, meat, coal and steel. It may look rapacious, but the Chinese are really just catching up with the greed of the rest of the world -- on a dizzying scale.

Stop when hunger is satiated, breathing becomes strong, limbs are strengthened and ears and eyes become sharp. There is no need of combining the five tastes extremely well or harmonising the different sweet odours. And efforts should not be made to procure rare delicacies from far countries.

More than two thousand years ago, the sage Mozi wrote of ancient laws regarding food and drink:

Sitting over my instant noodles, late at night after another unsettling banquet, I often find myself thinking about my Hunanese friend Liu Wei. In his modesty and restraint, his compassion, and his vegetarianism, he seems to embody a rather better attitude to eating, and, indeed, to life. Yet although his frugality looks counter-cultural in an era of widespread gluttony, it actually resonates with another, equally rich and ancient strain of Chinese thought.

Confucius, living at around the same time, did not eat much, and took care that the amount of meat he consumed did not exceed the amount of rice. His example has been used as a model for generations of Chinese children, urged by their parents to eat up their rice or noodles, and not to be distracted by their appetite for the accompanying dishes of fish or meat. And while businessmen and officials in early twenty-first century China stuff their faces with meat, fish and exotic delicacies, many people live at home on a simple diet of mainly grains and vegetables.

For the irony is that, despite the conspicuous consumption of banquet culture and that grotesque old stereotype of 'eating everything', the traditional diet of the Chinese masses could be a model for the entire human race. It's the way the older generation, the poor and the wise still eat: steamed rice or boiled noodles, served with plenty of seasonal vegetables, cooked simply; beancurd in many forms; very few sweetmeats; and small amounts of meat and fish that bring flavour and nourishment to the table. Unlike the typical diet of the modern West, with its profligate emphasis on dairy products and animal proteins, the traditional Chinese diet is minimal in its environmental impact, nutritionally balanced, and marvellously satisfying to the senses. After all my gastronomic adventures, I don't know if I can think of a better way to live.

And strange though it may sound, after all these tales of greed and omnivorousness, sometimes I think I'll end up becoming a vegetarian.

Perhaps, for the privileged in China, as in many other places, life has always been a struggle between the gentleman and the glutton, restraint and voracity. Liu Wei and me, sitting at dinner, he with his bowl of rice and beancurd, I with my shark's fin soup and stir-fried duck tongues, are just a continuation of this age-old tradition.