So just how much to vampires need to feed to stay healthy?

[definition of insane]

So we know vampires can survive for awhile without blood, but just how much do they need to be healthy?

I was having a conversation with a friend who said that there could be a Jossverse explanation for Angel's "girth" in the later seasons of Angel with blood being more readily available to him he may have just fallen victim to over-feeding and not enough action and just like a human, became less fit.

Anyone have any thoughts and ideas?

 

[white avenger]

Most of the time when either Spike or Angel feed, it's either from a coffee cup (about half a pint) or directly from a bag (a pint to a quart). We never know if they feed only once a day or several times, so that's not a whole lot of help' Vampires "in the wild" drain their victims, sometimes several in a single night, so that would have to amount to several gallons. Somewhere in between a pint and several gallons must lie an optimal amount, but we've never really been told just how much that is.

Spike seemed to only go a few days after escaping from them before he appeared to be on the verge of starvation. Angel, on the other hand spent an entire summer locked inside a steel coffin without suffering such ill affects that a small amount of blood wouldn't restore him to at least functioning if not full recovery (maybe he subsisted on fish blood all that time).

Both vampires lived on rats for some periods of time without suffering any long term ill effects, unless maybe that's what happened to Angel's hair...

Probably the minimal amount of blood required th sustain a vampire in healthy active condition is around a pint a day, but they can make do with a bit less.