What natural human needs does don quixote ignore?

In _Don Quixote_, there are many things that seem to be ignored by the protagonist such as reality. It seems easy to go about ignoring the world around him (be it madness or a choice), but one thing that seems to lend credence to the notion his state might not be a choice and he really is mad is how he is able to ignore the basic needs of the human body-eating, sleeping, and drinking.