Insect protein is healthy and sustainable. But now it is also at the centre of a far-reaching conspiracy theory. Throughout human history, insects have been on the menu. One of the earliest known depictions of entomophagy (insect eating) dates as far back as 30,000BC in the ancient cave paintings of Altamira in northern Spain, illustrating the gathering of bees. Today many people in Latin America, Asia and Africa consume insects regularly. In Mexico, for example, boiled and fried grasshoppers, "chapulines", are a popular bar snack and increasingly served in gourmet restaurants. (BBC News)