Over lunch today, Nora and I were trying to solve the world’s problems, and the conversation drifted to feed conversion ratios – how much food you have to feed to a chicken, pig or cow relative to the amount of food you get out as a result. If you’re going to eat meat, chicken seems to be the best bet, according to numbers in Naylor et al. in the Dec. 9 Science:

FCRs for chickens and hogs on an edible weight basis are roughly one-fifth and one-third, respectively, that of cattle.

In other words, it takes five times as much food in to get a pound out of your dead cow as it takes with a chicken, and three times as much for the cow compared to the pig. (Worldwatch suggests similar ratios, as does the farmed salmon industry’s trade association.)