Yasmin Alibhai-Brown: Eat only local produce? I don't like the smell of that

On Saturday night I committed untold crimes – against the nation, the planet, my grandchildren, and theirs. I should feel contrite and shabby, but I don't. Fourteen dined at our table and were fed patties of cassava and sweet potatoes, spicy Kenyan beans with tindola – vegetables like cucumbers the size of a baby's fingers. Also tilapia, a freshwater fish from East Africa, and a gruellingly difficult dish made with eight kinds of lentils, meat, oats and cracked wheat. Finally, almond and orange cake and raspberries in saffron cream. None of the ingredients was produced locally. This unrepentant sinner even chose Spanish raspberries, so sweet and more concentrated than the English variety.

Please don't tell Gordon Ramsay, he might come over and shout obscenities, maybe throw foodstuff out in a testosterone surge. He has just called for the banning of imported, "unseasonal" produce from restaurants. Some diners at his fancy restaurants say that this would make him a hypocrite; it would also make him one of those crusader environmentalists whose organic piety promotes unwholesome nativism and conservatism.

Indigenous Britons are in a mighty sulk over strangers on their shores, our weird languages, strong colours and tastes, and "unBritish" ways. Keeping out Kenyan beans and Caribbean pineapples is a sop to cultural paranoia, rising nausea. The country can't stomach any more foreignness and wants old simplicities back again. The rightful inhabitants think they want nothing but turnips and potatoes through our long winters, and in the summer, asparagus of genetically proven Englishness.

For centuries, our island nation has been seafaring and roaming, restless and lusty, hedonistic and insatiably curious, mercantile and capitalist, unable ever to stay put. Through that history, the land periodically goes through cycles of self-pity and dread of the very things it seeks, withdrawing into itself, its cliffs becoming fortresses. Sybaritic excess is followed by puritanism; internationalism is pushed out by petty patriotism. One thing for sure, this zeal will not be followed through to its logical end for that would mean the closure of Carluccio's and tandoori houses, and even the most fundamentalist food purists would not dare tread that far.

OK, maybe I should take more seriously the green arguments. So I do, and the calculations make no sense. Take a typical middle-class, UK family. They go on Ryanair trips and weekends abroad many times a year; drive hideously big cars, have umpteen gadgets and limitless consumer goods. But being conscientious, they will not buy corn sugar snap beans from East Africa. Big deal. Really do their bit, don't they just?

Writing in Time Magazine, Joel Stein incisively questions "locavores" who are "deeply Luddite, part of the green lobby that measures improvement by self-denial more than by actual impact". Furthermore, he implies, the injunctions encourage isolationism in the USA: "I'm going to keep buying food from my foreign neighbours. Because that is the only way Americans learn about other countries, other than by bombing them." Extreme, I agree, but indicating a link between politics and food that has gone missing in this Age of Environment.

Should good people be party to a vociferous movement which wants to refuse entry to "alien" foods? Look at the language used and you realise it is a proxy for anti-immigration sentiments: these foods from elsewhere come and take over our diets, reduce national dishes to third-class status, compete unfairly with Scotch broth and haggis, both dying out, excite our senses beyond decorum, contaminate the identity of the country irreversibly.

Turn to the clamour for the west to cut imported foods and a further bitter taste spreads in the mouth. If we decide – as many of my friends have – not to buy foods that have been flown over, it only means further devastation for the poorest. These are the incredibly hard-working farmers in the developing world, already the victims of trade protectionism imposed by the wealthy blocs. It means saying no to Fair-trade producers too, because their products have to travel to our supermarkets. Are we now to say these livelihoods don't matter because we prefer virtue of a more fashionable kind? Shameful are the environmentalists who are able to be this cavalier. They could only believe what they do if those peasant lives do not matter at all.

The 18th-century politician and gastronome Jean-Anthelme Brillat-Savarin wrote: "Tell me what you eat: I will tell you who you are." Localists tell us what to eat and turn Britons into panicked introverts just when we need global mutuality. Go buy foreign, spite Gordon Ramsay, and save the world.

y.alibhai-brown@independent.co.uk