Ok, according to the Lord of Madness, Illithids require brains (and psychic energy?) to survive. However, I gathered that if an illithid eats more than the required amount (more than one brain per week?) they can get some sort of power boost? What about a half-illithids, if I recall correctly they don't require brains to survive. If they eat a brain does that give them any kind of power boost? I'm the DM, so if there is no real rule for this kind of thing, I'm probably going to make up some unique, one-time power to be granted to the half-illithid.

Thanks in advance.