Researchers at the University of Toronto have discovered that people who live in areas jostling with fast food outlets are constitutionally less able to slow down and enjoy the simple things in life. Apparently, it's not just a question of additives and sugar ruining their powers of concentration: the Toronto research showed that just looking at a photograph of the McDonald's golden arch or KFC chicken is enough to give you the fidgets. As a result, you're less likely to appreciate images of natural beauty or an operatic aria than if you had dined at home with a proper knife and fork.

The panic around the moral and psychological damage of fast food – forget the obesity debate – is a familiar one. Behind Jamie Oliver's abhorrence of the Turkey Twizzler's empty calories was always a much deeper suspicion of what it represented: ignorance, indifference, a wilful inability to imagine a better way of feeding the future. It's for that reason that, back in the early 19th-century, moralists including William Cobbett churned out a whole array of "cottage economies" and "penny cookbooks" aimed at stopping the working classes from squandering money in the pie shop. These prim moral primers were full of bright suggestions for turning the scrag end of lamb and on-the-turn turnips into something that not only nourished body and soul but also saved pennies for a rainy day.

Fifty years later, Mrs Beeton had the moral dangers of fast food in mind when she announced to her readers her reasons for writing her venerable cookbook: she wanted to lure husbands away from the clubs and taverns into which they were apt to dive at the end of a long working day, desperate for a quick supper. Beeton's solution was to set before the weary homecomer a series of delicious labour-intensive dishes – the sort of thing no short-order cook would contemplate. Her soups often took 15 ingredients and required a 10-hour simmer.

The point of all these initiatives, from Cobbett to Oliver, has always been less about getting nutritious food inside people than to teach them a lesson. Learning how to make and eat slow food is to develop a capacity for delayed gratification that, in turn, fits both maker and consumer for life under capitalism.

Historically, those who could learn to wait, who knew the importance of investing their time as well as their money, would be the ones to profit in the great game. In an era of self-help – Samuel Smiles's classic manual came out in the same year as Mrs Beeton's work – those who managed to avoid the lure of the pie shop in favour of homemade soup were the very people who had the best chance of winning at life.

This is much more than a metaphor. The University of Toronto researchers discovered that those North Americans who live in areas where there is a high density of fast food "cues" do actually find it harder to save for the future. Still, you can't help feeling that behind the well-meaning implication that rational citizens should eschew eating in the street if they want to enjoy the good life, complete with Puccini and a pension, is a slightly different – which is to say, very old – message. And it is this: anyone who does choose to dive into KFC rather than go home for supper is morally derelict or simply ignorant. Either way, they're heading for a fall.

What all those Victorian moralists missed – just as the Toronto report ignores – is that fast food is the emblematic product of maturing and late capitalism. Urban workers, forced to work longer and longer hours, do not have the time to invest in cooking from scratch. Those who are obliged to live in shared accommodation and rented digs may not have the right equipment for making real food slowly (Agas don't fit into bedsits; microwaves do). When you are exhausted after a 10-hour shift, then soup is fiddly to consume on the way home. Burgers and kebabs, by contrast, are easy to eat with one hand and require neither plates nor knives. Far from being the refuseniks of capitalism, unable to master its first principle of delayed gratification, the people who rely on fast food outlets are its honourable foot soldiers. We should salute them.