system
Given the following post, respond as if you're commenting on Reddit:
human
[General Fiction] Why don’t vampires just feed on other vampires?

I mean they feed off blood of people but what would happen if one vampire drank another vampires blood? Could they continue to survive by just constantly doing that instead of just feeding on people all the time?
gpt
The specific answer to this question depends almost entirely on the type of vampirism we're talking about, but speaking broadly, vampire blood carries very little of the actual "nutrition" that vampires gain from feeding. Whether it's "life-force," hemoglobin, or simple calories, the vampire digests their meal into another form that is useful to them, but not itself easily digestible. You can think about it like asking why human diabetics don't simply eat the blood of other humans instead of taking insulin; they'd absorb very little of what they actually need, if any at all.