In this verse, the original Greek word that is here translated "witchcraft" is "phar-ma-kia"... the same word from which we derive "pharmaceuticals"...and some translations actually render this verse as "druggery" rather than "witchcraft" or "spiritism".
I'm using this definition of "witchcraft," and what it implies (i.e. doing something to change your perspective), and simply remarking on the fact that fasting (and sleep deprivation), can cause some extremely weird and hallucinatory experiences.
It's a pretty weak distinction, if you want to say it's okay to stop eating to experience something fake, as opposed to ingesting something to experience something fake. In both instances, you're going to alter your experience, experience something you otherwise would not experience, etc. Both are illusory.