I think the banana makes you sick because bananas make you sick. Bananas don't make me sick and I can tell because I don't get sick when I eat a banana. I can be around people who eat bananas and that helps because then I don't feel excluded.
Bananas are okay though. Maybe you're just doing it wrong.
according to my knowledge bananas do not make us sick, will automatically make us more energetic if run it.
You sound like you take your bananas seriously. :)