Why most advice on the food we eat is just junk

THE other week, I went to see a nutritionist in Edinburgh; my idea was to find a sensible way of gradually losing some weight. So for an hour or so I chatted to her about my current diet, my deadline-driven lifestyle and the amount of time I spend on First ScotRail trains, an environment where dietary options tend to be limited to whatever's left on a trolley full of crisps and chocolate.

She listened to all this with apparent attention, and then gave her verdict. "Oh, just cut out wheat and dairy completely for a month," she said, "and tell me how you get on." I remonstrated that this seemed a bit extreme; she said I could have goat's and sheep's milk, but nothing with a whiff of cow. I said what about sandwiches, she said no, it was rye bread and wheat-free oatcakes from now on. I said that I could not do this without becoming exactly the kind of whiny food-fetishist I most despise; she said it was up to me, but it was what my long-term health required, in her opinion. We stared at each other for a while across a gulf of incomprehension; then she charged me a gut-wrenching sum, gave me another appointment in a month's time and wished me luck.

And I thought about my culture-clash with the nutritionist this week, when the shockwaves from Jamie Oliver's latest television food show began to spread across the media. This time around, Jamie began by visiting Rotherham, where he discovered a few folk – mainly poor and working-class – whose dietary philosophy seemed best summed up in the phrase "Can't Cook, Won't Cook". One woman literally didn't know how to boil water; another had two young children who had never eaten a meal cooked at home and whose only experience of hot food came from takeaway chips and kebabs. Oliver was apoplectic. "F****** hell," he roared. "It's f****** Great Britain. It's 2008. I've been to Soweto and I've seen Aids orphans eating better than that."

Yet, as Oliver is beginning to realise, just echoing the style of other bullying television reality shows and telling ordinary people that their diet is dire is not enough. For we are what we eat, not only physically, but socially and culturally too; and to attack our diet is to attack a profound part of our identity, the very keystone of our interaction with the natural world and with other human beings. For myself, I'm lucky enough to live in an environment where there are greengrocers on the corner, and where people pride themselves on sitting down to a decent home-made dinner at least three or four times a week. Yet I sobbed on the way home from the nutritionist's; because in telling me I should no longer eat as I used to, she seemed to be saying that I should say goodbye to my life, and to all the people in it who – quite rightly, in my view – would burst out laughing if they were to hear me uttering pusillanimous, life-denying phrases like, "Oh, no, I can't touch dairy", or "is there animal fat in that?"

So if the session with the nutritionist was disturbing for me, just imagine, if you will, what is being asked of people like the young, poor, single parents in Jamie Oliver's programme, who are being told that they must change their diet completely. It's not only that the food outlets in their local area probably make no provision for that kind of shopping and cooking. It's not even the killer fact that Britain's entire food economy depends on the high consumption of heavily processed junk food, and that the industry will therefore spend countless promotional millions ensuring that the trade in it continues to grow. It's that, in asking people to turn their backs on the burgers and chips and kebabs and curries that form the common social currency of their lives, they are asking them to walk away from the communities in which they live, and from the only basic food economy they know.

Now, of course, the coming of this fast-food economy has been a social and nutritional tragedy, deeply disempowering to parents as creative providers for their children and shocking in its long-term health implications. But if the history of Britain since the industrial revolution tells us anything about this kind of nutritional poverty, it's that the one thing which never improves matters is the sound of the boss class exhorting the masses to be sensible. What does work is vigorous government intervention and regulation – so score one for the SNP government in Scotland, with its plan to provide healthy free school lunches for all five- to seven-year-olds – combined with self-organisation by the people at the sharp end: ordinary folk who, like the temperance campaigners of the 19th century, are tired of being exploited by an industry whose products damage their health and corrode their family life.

And until such time as a movement like that begins to emerge – well, I have switched to goat's yoghurt in the morning and given up my lovely old oatcakes for a miserable wheat-free alternative. But I am struggling to find the right balance between the society I live in – with its long working hours, its high-energy snacks and its well-justified scepticism about the long-term future – and the sober advice of the nutritionist. And so long as I struggle, I am not going to sit in judgment on people who face far tougher social and economic pressures; and who, finding a convenient, junk-based food culture on their doorstep, are not equal to the task of challenging that culture single-handed, or to starting the outright social revolution towards which Jamie Oliver's restless questioning of our entire food economy increasingly seems to point.