We know that if you do less activity, then there is less energy spent from ingested food. The excess must be excreted or stored - often both.

Since metabolism refers to all chemical processes involved in converting food to usable activity, if a slowdown occurs, then food is digested slower and less efficiently, usable energy is extracted less quickly, energy is expended less efficiently, and so on. I imagine that depending on where the efficiencies are comparitively lowest would control how a slower metabolims manifests. Getting fatter easier could be one result. Needing to eat more is another. Requiring more rest-room visits could be another.

Wade.