What with all the hoo-hah surrounding the pope's recent British holiday, the news that Nando's has bought the Gourmet Burger Kitchen chain for £30m may have escaped your attention. In many ways it's the 21st-century equivalent of Little Chef absorbing Wimpy, albeit markedly more middle-class than that. Both chains specialise in upmarket fast food: the kind of place you don't feel thoroughly ashamed to be seen in, unlike their more established and reviled mass-market competitors.

One cold morning about two years ago, I sat in the window of a McDonald's tucking into a sausage-and-egg McMuffin. It was a bit like sinking my teeth into a small, soft woodland creature with a light dusting of flour; one which thoroughly enjoyed being eaten and responded to each bite by gently urinating warm oil down my chin. It was a strangely comforting experience, until I realised that some – not all, but a reasonable percentage – of the passersby outside the window were regarding me with a combination of pity and contempt as they scurried past. Sitting in the window of a McDonald's, I realised, is a bit like self-harming in a glass booth. People judge you for it.

Not so the Gourmet Burger Kitchen. It has about 50 branches around the UK, but since most of them are in London, chances are you haven't visited one. It's a posher, ostensibly healthier Burger King: fresh, chargrilled, 100% Aberdeen Angus patties served inside buns "made to a secret recipe by our artisan baker". But that much you could probably guess from the name. What's truly shocking, the first time you're confronted with a Gourmet Burger, is the sheer quantity of food involved. Eating one is a bit like attempting to cram a fortnight's worth of clothing into a child-size suitcase, or falling face-first into a meat sofa.

You've got two options: tackle it with a knife and fork (the coward's way out), or dislocate your jaw in the manner of a boa constrictor swallowing a foal, and heave it into your gullet, driving it home like a Victorian taskmaster pushing a buttered eight-year-old into a narrow chimney flue, taking care not to let the top half of the snooty artisan bap smother your nostrils on the way in.

Order chips, incidentally, and your burger will be accompanied by a generous helping of deep-fried slabs the size and weight of piano keys. Eat there at lunchtime and you'll spend the rest of the day feeling as if you're incubating an immense, spherical beef-baby. And caesarean delivery sadly isn't an option. Before bedtime, you'll understand how it might feel to give birth to a banister.

Even though a posh cheeseburger contains roughly 805 calories, compared with 490 calories in a Big Mac, there's no shame attached to the public enguzzlement of Gourmet Burgers, partly because of the emphasis on fresh ingredients, but mainly because it's a thoroughly middle-class form of indulgence. (Don't get me wrong, I like a Gourmet gutbuster now and then – but I couldn't honestly say I enjoy it more than a Burger King Whopper. Both are definitely superior to the Big Mac, however; to my mind, Big Macs taste a bit like a burger that's just been sick down its own front on a long car journey.)

Nando's, while not as posh as GBK, serves up spicy flame-grilled chicken, which makes eating there feel decidedly less shameful than a trip to KFC (fair enough, since eating KFC is like squeezing a sponge full of poultry- flavoured oil into your gob). But the health benefit of Nando's flame-grilling technique is perhaps slightly offset by the endless free drink refills; while gnawing at their chicken, your diet-conscious kiddywinks can guzzle as much cola as their guts can withstand.

So, then. It seems the key to nurturing a successful chain of fast-food restaurants in modern Britain is to provide a less reprehensible version of something popular (burgers for GBK; chicken'n'chips for Nando's), while still enabling your customers to indulge in potentially ruinous gluttony. It's a simple formula, and I think I've spotted a gap in the market: fry-ups. Everyone loves a full English breakfast, but the traditional greasy spoon has an image problem. I propose a chain of health-conscious caffs where the eggs are free-range, the tea and coffee are Fairtrade, and the sausages and bacon are cooked on George Foreman grills, right there at the table.

Oh, and the meat in the sausages and bacon comes from the customers themselves. Your first cup of tea contains a local anaesthetic; while you read your paper, simply slice a thin rasher of thigh off your leg and pop it on the grill. Two rashers if you want to lose weight. It's the ultimate in locally sourced produce: 100% organic, extremely environmentally friendly, and, if taken up by large numbers of people, it will go some way to solving the global food crisis.

The only downside I can think of is the blood leakage, although I'm sure, given time, I'll think of a solution. Probably involving vinyl seats and black pudding. I only need a couple of million to get going. Who's in?