49% of calories from the world's crops are consumed by livestock, not people
“Meat and dairy consumption is increasing globally and generally increases with wealth (11, 27). Between 1961 and 2009, the percentage of calories from crop production consumed as food decreased from 57 to 51% (fig. S4). Although crops used for animal feed ultimately produce human food in the form of meat and dairy products, they do so with a substantial loss of caloric efficiency. If current crop production used for animal feed and other nonfood uses (including biofuels) were targeted for direct consumption, ~70% more calories would become available, potentially providing enough calories to meet the basic needs of an additional 4 billion people (28)”
Paul C. West et al., "Leverage Points for Improving Global Food Security and the Environment," 345, no. 6194 (2014): 326, accessed on July 18, 2014, doi: 10.1126/science.1246067