If you follow a diet based on the recipes in The Vegan Cookbook (Alan Wakeman & Gordon Baskerville, Faber and Faber, London 1996 - see below) you'll certainly find yourself spending a lot less on food on a personal basis, but the consequences of a shift to a vegan diet among the population at large would be considerably more far-reaching.
   Animals reared for their meat have been calculated to use 90 per cent of the plant food given to them simply to sustain their own bodily processes. Only 10 per cent finally arrives on the plates of omnivores. It would be hard to imagine a more uneconomic or wasteful way of using the world's resources. Consequently, if there were a major shift towards veganism in the industrialized nations, the prices of plant foods would fall everywhere, especially in the Third World.