Light, Sweet Porridge by mike · 2006-03-28 An average of more than 7 calories [29.3 kJ] of fossil fuel is burned up for every calorie of energy we get from our food. This means that in eating my 400-calorie [1.7 MJ] breakfast, I will, in effect, have consumed 2,800 calories [11.7 MJ] of fossil fuel energy. (Some researchers claim the ratio is as high as 10 to 1.) But this is only an average. My cup of coffee gives me just a few calories of energy, but to process 1 pound of coffee requires more than 8,000 calories [33.4 MJ] of fossil-fuel energy — the equivalent energy found in nearly a quart [.94 L] of crude oil, 30 cubic feet [850 L] of natural gas or about 2.5 pounds [1.1 kg] of coal. Old but good: The Oil We Eat. Related