The wasteful young must learn the magical thrift of their elders

Hypocrisy is the easiest vice to slip into casually of an evening. On Tuesday, for example, I inflamed my social conscience by going to a fundraising event for Feedback, the charity that campaigns to end food waste. I listened with rising outrage to speeches full of desperate statistics. At least a third of all the food produced globally never gets eaten. The water that is used to grow this wasted food would be enough to service the domestic needs of nine billion people – more than the entire population of Earth. Every year, consumers in rich countries such as Britain waste almost as much food (222 million tonnes) as the entire net food production of sub-saharan Africa (230 million tonnes).

I went to bed filled with disgust at the profligacy of my fellow man. Meanwhile, in the darkness of my kitchen cupboard, the potatoes I bought two weeks ago began to send out shoots, like little arms raised in supplication. Too late: I chucked them out today because they’d gone all green and wrinkly.

“Forbear to judge, for we are sinners all,” said Shakespeare. Right again, O wise bard – except in one respect. There is actually a group of people in this country who, without any fuss or moral preening, consistently do the right thing for the environment. They are known as

Old People.

Consider the numbers. People born in the Eighties and Nineties – the millennials who profess such a deep concern for environmental issues – throw away almost 50 per cent more food than those aged over 65. They misjudge portion sizes, buy exotic ingredients that are hard to reuse, and are less likely to use leftovers. Only 17 per cent of under-35s say they never waste food, compared to 40 per cent of pensioners. I can’t find an equivalent figure for Generation X-ers like me (I am 46), but I doubt it would cover us in glory.

The truth is, frugality is an art form – one that most of us have had no occasion to learn. My mother, who grew up during the last years of war and rationing, can make a chicken feed a family for a week – first as a roast, then as cold cuts, risotto and finally soup. Every time she does this I feel like I am watching a conjuror at work, pulling sustenance instead of silk handkerchiefs out of the air.

I marvel, now that I have truculent children of my own to feed, at the things she persuaded my sister and me to gobble down, even as toddlers. Tripe and onions, dainty slices of calves liver, lentils with everything, and (a special treat this – the closest we ever got to chicken nuggets) breaded lambs brains, fried to a golden crisp.

Eating nose to tail like that is one of the most effective ways for carnivores to reduce food waste. But that, too, has fallen out of fashion. The only people who eat liver these days are old men in raspberry cords, closing their eyes and dreaming of a vanished England.

It isn’t exactly virtue that makes old people live more sustainably than the rest of us. They darn socks, patch elbows, rescue scraps of soap from the plughole, hem fraying edges, reuse clingfilm – not just because they know how, but because they know why. They understand that stuff is finite.

Most Western countries, including Britain, now produce and import roughly twice as much food as they actually need. Although there are certainly hungry people among us, as a nation we are awash with surplus goods. We have become (unlike the food we throw away) spoiled rotten.