Governments may have to persuade people to eat less meat because of increasing demands on water supplies, according to agricultural scientists investigating how the world can best feed itself. Currently up to 90% of all managed water is used to grow food. "Western diets, which depend largely on meat, are already putting great pressures on the environment. Meat-eaters consume the equivalent of about 5,000 litres of water a day compared to the 1,000-2,000 litres used by people on vegetarian diets in developing countries. All that water has to come from somewhere."