In response to questions about the energy-efficiency tables I listed
yesterday, I want to explain the meaning of the figures listed for
biological transportation methods such as bicycling: The "fuel" is food,
and the amount of fuel is the number of food calories consumed. It
includes the basal metabolism rate. For example, the energy efficiency of
bicycling is quoted as 18 passenger-km/MJ. This means that, to maintain a
constant supply of stored biological energy, while bicycling 18 km and
simultaneously doing all the other things a human body does (heart, lungs,
etc.), you must consume 1 MJ (240 kcal, or 240 dietician's Calories) in the
form of food (i.e. chemical energy that is then metabolised). - Art Hobson