There is a theory that insulin regulates metabolism. In times of energy
excess, insulin resistance occurs and there is more proinsulin produced,
this has an effect on sugar metabolism - blood sugar is raised because
it is not entering cells, some people get non-insulin dependant
diabetes. The effect of exercise is to increase insulin efficiency in
the muscles, sugar leves fall, and health increases!! In energy deficit
insulin resistance induces a ":thrifty" pheontype, and protects you from
death from starvation,
