Exactly how much pizza can one of these things consume before he a) explodes b)stops being hungry c) gets tired of it?

I read somewhere, that a normal, average sized, adult with a "normal" life style might be able to consume, and utilize - for energy to run on, or repair tissues, not to build fat - two thousand calories a day. A large, muscular logger, working long hours of hard physical labor in very cold weather, might consume and utilize as much as four thousand. For a teen-ager in a growth spurt, six thousand is possible.

Peter.