Question: how much energy does it take to make a burger?
Answer: 6 times (well 3.2-8.85) as much (primarily fossil fuel) energy goes into a burger as calories in the burger. A Big Mac has 540 calories or 2.26 MJ (1 MJ = 239 kcal). Compared to the 7.3-20 MJ of energy to produce the burger that gives us a range of 3.2 to 8.85.