If I was an LLM and one of my main tasks was to answer questions, then I would expect a lot of "what if" type abstract queries by bored people. Obviously, people like that don't want a literal answer - the context is crystal clear.

It's not a bad question either - it can illustrate the efficiency of the human body, or help you get a better feel for different quantities of energy.

It even hedged its bet by very explicitly explaining why consuming gasoline or uranium is a bad idea.