How surprising is this? Think of a thin person and a large one of the same height. Consider they're both sitting normally dressed at room temperature. The body

How surprising is this? Think of a thin person and a large one of the same height. Consider they're both sitting normally dressed at room temperature. The body will dissipate heat over its surface area. Surface area is proportional to linear measure squared, volume to linear measure cubed. But given constant height, surface area varies with linear measure, and volume to linear measure squared. So a quadrupling of volume/weight results in a doubling of surface area. Now if maintaining body temperature above room temperature is a significant expenditure of energy, it would be expected that larger people are more energy efficient and thus less 'efficient' at burning calories per unit weight.