A world in which we all eat the same food will end up with a side of disaster

Supermarket shelves filled with the exotic give a false impression, warns environmentalist Simran Sethi. Her new book exposes the dangers eating a small number of the same things

"Right now, three-quarters of our food comes from 12 plants and five animals," says Simran Sethi. She is almost incredulous, comparing it to a someone suggesting an investor plough all their money into just one stock. "No sane person would say or do that, but with food that is exactly what is happening."

The assertion might seem surprising: supermarkets appear to be bristling with foods that would have seemed exotic 50 years ago. But, Sethi says, that is an illusion: "On a smaller local level there is more diversity in food, but the global trend that we see is towards sameness; it is towards that same homogenisation we see in clothing or technology - you can go to any part of the world and find someone wearing Levi jeans and holding an iPhone."