Not only is the global population increasing, we are living longer and becoming more affluent. As incomes increase, diets become more energy-dense and meat becomes a larger proportion of the diet. These changes in population and cuisine have led to a tremendous rise in the demand for animal-source protein. The competition between livestock and humans for grains and other high quality plant foods, whether real or perceived, is recognised as a major challenge. This has become more complicated with the diversion of grain to the production of biofuel.