My educated guess is that it is just healing the digestive system or increasing digestive enzymes — that makes good nutritious food completely absorbed in few hours leaving very little residue for expulsion (increased efficiency from an engineer's perspective) and not
so good food getting quickly expelled from the
body — which makes the person productive in whatever they are supposed to do (Macro level action, taking care of digestive system for example, in setting your
body in the correct path for best functioning or preventing you from getting any disease or
letting you
recover fast).