MB 24: Permissible - Even elaborate foods that would otherwise be considered haughtiness are permitted, even for a person who is not ill, since he is eating for health reasons and not for haughtiness. Certainly it is permitted to drink potions or liquid medications.
89:4. One who is thirsty or (25) hungry is considered as if he is ill and if he can concentrate on praying, he should pray, and if not, he can delay praying until he has eaten and (26) drunk.
MB 25: Hungry - This refers to somebody who is _very_ hungry.
MB 26: Drunk - We can infer that he is not _required_ to eat. The reason [that he is not required] is that we have lost the ability of full concentration (*) but if one wants to eat or drink to improve concentration is permitted. [* meaning that even eating will not restore the ability to fully concentrate - NW]