Cursing, I reached up and grabbed it. The cover was almost as compelling as the spine: a photograph of a taut and sweaty male stomach, framed by the words “BANISH” and “YOUR BELLY”. In case there remained any confusion as to the subject matter, a helpful subtitle was printed beneath: “The Ultimate Guide for Achieving a Lean, Strong Body — NOW.”

That night I sat up in bed, my copy of Banish Your Belly balanced on my belly. I began to read.

Within minutes I had learnt about the 39-year-old author’s “midriff crisis” and how he had jogged away his man-fat, “often ending my runs by sitting in a tub of iced water to stop the swelling in my legs”. Before long, I was immersed in my own belly-banishing fantasy: I imagined myself dresssing like Tommy Lee, and turning up to Hollywood parties naked except for baggy surfer shorts, tattoos and facial jewellery . . .

As you might imagine, Los Angeles is one of the thinnest cities in America (the actual thinnest is Denver, Colorado). There is really no excuse to be fat here — what with the mountains, the beaches and the deserts, you don’t even need to join a gym. Then there’s the body-image narcissism encouraged by Hollywood, and the general culture of life-extension over indulgence.

And yet, as if to mock us, the city’s restaurants offer some of the most criminally calorific menu items this side of a Welsh fish’n’chip shop. Staples include roast beef sandwiches served with a separate bowl of dipping fat (known as a “French dip”) and half-pound hamburgers with chilli con carne and cheese slathered on top. Not to mention the burrito, a tortilla football stuffed with meat, rice, guacamole, sour cream and cheese.

For those of us not of an outdoors nature, who traverse this scorching megatropolis via air-conditioned car (in London, you at least have to sweat your way to the Tube station), Los Angeles can be tragically belly-enhancing.

Halfway through Banish Your Belly, I realised my biggest problem: keeping track of calories. It’s easy when you’re at home, but impossible when you’re out — ie, most of the time. Surely, in these days of accounting software and online banking, there must be some kind of electronic gadget that can help?

A trip to Google provided the answer: a website called FitDay.com will count calories for you online. You tell it your age, height, weight and general activity level (“sedate” in my case), then use a system of pull-down menus to keep track of everything that passes your lips. If you do any exercise (I don’t), you monitor that also. By midnight every day, FitDay will compile for you a spreadsheet of all calories burnt and consumed, along with your resulting surplus or deficit. Best of all: it’s free.

I soon became addicted. After two weeks of using FitDay, however, I noticed the flaw in this seemingly perfect belly-banishing system: it’s easy to lie to a computer. Like a dodgy accountant at tax time, I soon worked out ways to categorise my foods so that I always came out with a massive calorie deficit. And yet, in reality, my belly was going nowhere. Disillusioned, I gave up. My FitDay charts remained unfilled. My belly continued to grow.

But technology, as always, remained ahead of me. A few days ago I discovered a new service called Nutrax. This allows you to use a camera phone to snap a picture of your restaurant meal, which you e-mail to an online specialist, who then e-mails you in return a breakdown of its nutritional value and calorie content. Restaurants across Los Angeles are already full of diners taking photographs of their food — surely a challenge to chefs to make their dishes impossible to analyse (if they aren’t already).

But one issue comes to mind: by the time you’ve ordered your meal, photographed it, e-mailed the photograph and received your calorie count in return, isn’t it too late? By that time, I would already be half way through my chilli-burger.

All of which confirms what I’ve long suspected: buying diet products is a lot more fun that actually using diet products, no matter how high-tech they become. As for Banish Your Belly: it’s back on the shelf, this time in my office. The title still calls out to me. But I’ve learnt to ignore it.

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