... cattle require 28 times more land, 11 times more irrigation water, five times more greenhouse gas emissions and six times more nitrogen fertilizer — per calorie consumed — than the four other animal food sources.

While energy use intensities for fruit production vary significantly depending on location and production methods, fruits, on average, have the highest energy index score, primarily because they have low-Calorie densities relative to other foods.

http://link.springer.com/article/10.1007/s10669-015-...