So, slow metabolism is not a disease, it's not a genetic disorder, it is simply a result of the fact that someone is spending too much time on the couch.
I think this gets lost a lot when people talk about "slow metabolism", they turn it into this thing they're just helpless to influence, like they're just cursed with a slow metabolism and that's that. It's not like that at all, which is why I don't like the term. It just hides the reality of the situation.