Within five minutes of my desk can be found: an Italian delicatessen, a Vietnamese pho house, a pizzeria, two Chinese, a Thai, and an Indian “with a contemporary twist” (don’t knock it till you’ve tried it). Can such bounty be extended over the Earth?

Yes, it can. It’s already happening. And in what amounts to a distillation of a life’s work writing about food, Dan Saladino’s Eating to Extinction explains just what price we’ll pay for the global food industry’s extraordinary achievement which hopes, not only to end world hunger by 2030 (a much-touted UN goal), but to make California rolls available everywhere, from Kamchatka to Karachi.

You think your experience of world cuisine reflects global diversity? The problem with my varied diet (if this is Wednesday then this must be Thai red curry with prawns) is that it’s also your varied diet, and your neighbour’s; in other words, it’s rapidly becoming the same varied diet across the whole world. Humanity used to sustain itself (admittedly, not too well) on 6,000 species of plant. Now, for more than three-quarters of our calories, we gorge on just nine: rice, wheat and maize, potato, barley, palm oil and soy, sugar from beets and sugar from cane. The same narrowing can be found in our consumption of animals and seafood. In short, we’ve learnt to grow ever greater quantities of ever fewer foods.

Saladino, a presenter of Radio 4’s The Food Programme, is in the anecdote business. He travels the Earth to meet his pantheon of food heroes, each of whom is seen saving a rare food for our table – a red pea, a goaty cheese, a flat oyster. So far, so magazine-y. And there’s nothing to snipe at in the adventures of, say, Woldemar Mammel who, searching in the attics of old farmhouses and in barns, rescued the apparently extinct Swabian “alb” lentil; nor in former chef Karlos Baca’s dedication to rehabilitating an almost wholly forgotten native American cuisine.

That said, it takes Saladino 450 pages (which is surely a good 100 pages too many) to explain why the Mammels and Bacas of this world are needed so desperately to save a food system that, far from breaking down, seems to be feeding more and more food to more and more people.