A comment about the recent post regarding James E. McWilliams' book, Just Food, noted that, "he ignores the elephant in the room--overpopulation. Even if everyone in the world turned vegetarian overnight, every year the world's population would continue to grow at an ever-faster rate."
Actually, McWilliams does speak to that issue, mostly in relation to the energy and land (which would need to be cleared/converted) required to produce meat for the earth's current population as well as the population growth expected. For example, "grains produce between 1.5 to 2.5 food calories for every calorie of fossil fuel burned."
Conversely, even "the production of range-fed beef requires 3 calories of fossil fuel for every 1 calorie of meat produced." Worse, feedlot cattle require 33 calories of fossil fuel.
The situation is complicated by the fact when a nation's income increases -- think China -- the demand for meat skyrockets. That means converting more land to grow cattle, with all the inefficiency of energy use expanded further.
McWilliams does advocate a concerted effort to increase "aquaculture" -- that is, fish farming, a technique for which he offers figures illustrating its superior efficiency.
Thus, it is evident that McWilliams is not advocating the cessation of meat consumption world-wide. He simply says there is a better way than clearing the Amazon basin for pasture or confining hundreds of thousands of cattle to feedlots and applying growth hormones and antibiotics.
If you cannot afford to buy a copy, I urge you to check the book out and read it when it arrives at your local library.