In the United States, the food industry accounts for 14% of national energy use1, and thirteen calories of energy are required to bring to the plate each calorie consumed by people2.
1) Canning, Patrick, Ainsley Charles, Sonya Huang, Karen R. Polenske, and Arnold Waters. Energy Use in the U.S. Food System, ERR-94, U.S. Dept. of Agri., Econ. Res. Serv. March 2010.
2) Pimentel, D., Pleasant, A., Barron, J., Gaudioso, J., Pollock, N., Chae, E., Kim, Y., Lassiter, A., Schiavoni, C., Jackson, A., Lee, M., and Eaton, A. 2002. U.S. Energy Conservation and Efficiency: Benefits and Costs. College of Agriculture and Life Sciences, Cornell University, Ithaca, NY