Fat people can survive starvation longer than thin people.
In both instances, we would like to find a relationship between the chemical characteristics of a food or fuel and the amount of energy it will provide upon oxidation. In the case of foods, that energy might be used fairly soon, or it might be stored for later use, perhaps during a period of starvation. In the case of fuels, we'd like a fuel which gave us lots of energy upon combustion, yet was easy to transport, store and dispense. Let's compare the structures and the measured heats of combustion of some of these materials to see whether we can get some clues. After all, we don't eat food by the mole, but by the gram or kilogram.