We may all go over the top with food now and again but there is nothing about avoiding obesity that we don’t all know in our hearts

A BUSINESS lunch in Chicago. We’re in a steakhouse and thinking, “When in Rome . . .” The Irish contingent dig in manfully, and woman-fully, to creamed spinach, mounds of chips that appear to be tossed in cheese and truffle oil, and of course the steaks themselves, which stand two inches off the plate. Even the bread rolls are the size of babies’ heads. Our host puts us to shame with his small piece of plain white fish and some string beans.

Lunch, on the scale we’ve ordered, is not just for wimps, it’s for out-of-towners. “Do you want me to bag that up?” the waiter asks of our half-full plates. “Oh God no, take it away.”

We’re disgusted with ourselves, but it’s the same again at dinner.

The Irish do the dog on it, and the Americans hold back. The lady to my left confides that she NEVER normally eats steak – it shuts her system down. Red wine makes her breathless; fries, well nobody eats fries; onions give her gas, ice cream makes her head-achy, and so on and on. Even after sushi she’ll take a kick-boxing class. This meal will stay with her all week, she says with a martyred roll of the eyes, as the Irish wolf all the way through to dessert, reckoning we’d soon be back home to soup and brown bread and with Lent coming down the tracks.

Next day as penance, I set out to buy a copy of a book that’s topping the New York Times best-seller list (self help category). It’s hard to miss – there are five shelves of it on display in the local bookstore. Michael Pollan’s Food Rulesis slim for the money, but that’s clever. All you have to do is learn the simple rules and you too can be slender. Pollan, a professor at Berkeley in California, is the author of several previous bestsellers on food, and a self-declared sceptic of nutritional science. Instead he puts his faith in traditional food culture, and advises us to eat the kind of food our ancestors would recognise. Food Rules is a distillation of all he knows – 67 pointers on what to eat and what not to eat. He dedicates it to his mother, “who always knew butter was better for you than margarine”.

Really, there is nothing in this book that we don’t all know in our hearts. It’s just a new and entertaining way of saying it. We eat too much processed food in the West. It is killing us. Fact. Populations who are still eating traditional diets are healthier – think of the Japanese and their low obesity levels – but hear this: people who wean themselves off the western diet can improve their health dramatically. Fact again. Don’t listen to scientists, Pollan says; don’t get caught up in the pseudoscience of food, just listen to common sense.

This will be balm to the ears of grandparents horrified at the things they see fed to their grandchildren – things that don’t even look like food any more: rubbery batons that turn out to be cheese, pizza that comes out of plastic and tastes of plastic, yogurt that’s actually whipped up chocolate bar, biscuits that have morphed into cakes, and all the rest. All of it piled high in the local supermarket. Irish children are eating their way towards one of the highest obesity rates in the world, despite a government taskforce set up more than five years ago to tackle the problem. A copy of Pollan’s book sent to every parent in the land might help.

Here is some of his best advice: If it came from a plant, eat it; if it was made in a plant, don’t; it’s not food if it arrived through the window of your car; it’s not food if it is called by the same name in every language (think Big Mac, Pringles); avoid food products with more than five ingredients; avoid foods you see advertised on television; don’t eat breakfast cereal that changes the colour of the milk; drink the spinach water; eat all the junk food you want, so long as you cook it yourself; have a glass of wine with dinner; stop eating before you are full; eat when you are hungry, not when you are bored; buy smaller plates and glasses; spend as much time enjoying the meal as you spent preparing it; eat meals.

This last piece of advice looks ridiculously obvious, but we’ve become a nation of grazers, eating at our desks or standing up, bolting down sandwiches on the street or running out the door with a bar, instead of breakfast.

Clearly, we can’t all afford to follow Pollan’s advice, some of which is a little aspirational – such as buying all one’s snacks at farmers’ markets or eating wild game as much as possible. However, the central message, which is to keep away from highly processed or downright invented foods, is compelling. You find those foods in the central aisles of supermarkets, he says, so next time you shop, stick to the edges.

And, next time you’re out, give the creamed spinach and fries a miss.