The world's population is projected to reach 11 billion by the end of the century. Feeding that many people will be a challenge, and it is further complicated by the impact of climate change on agriculture. That is why some people advocate an unusual way to boost the food supply and feed people sustainably: by eating less meat, and more insects.

About 2 billion people already eat bugs. Mexicans enjoy chili-toasted grasshoppers. Thais tuck into cricket stir-fries and Ghanians snack on termites. Insects are slowly creeping onto Western menus as novelty items, but most people remain squeamish. Yet there are three reasons why eating insects makes sense.

First, they are healthier than meat. There are nearly 2,000 kinds of edible insects, many of them packed with protein, calcium, fibre, iron and zinc. A small serving of grasshoppers can contain about the same amount of protein as a similar sized serving of beef, but has far less fat and far fewer calories.

Second, raising insects is cheap, or free. Little technology or investment is needed to produce them. Harvesting insects could provide livelihoods to some of the world’s poorest people.

Finally, insects are a far more sustainable source of food than livestock. Livestock production accounts for nearly a fifth of all greenhouse-gas emissions – that’s more than transport. By contrast, insects produce relatively few greenhouse gases, and raising them requires much less land and water. And they'll eat almost anything.

Despite all this, most Westerners find insects hard to swallow. One solution is to use protein extracted from bugs in other products, such as ready meals and pasta sauces. Not having to look at the bugs, and emphasising the environmental benefits, might make the idea of eating insects a bit more palatable.