Everyone has at least that one treat they would have even when one doesn't have an appetite or when sick. mine would be popcorn, no matter how sick or nausea's i feel, popcorn is the one thing i can always eat.
It depends what the illness is. If I have a stomach complaint I really can't eat anything but if I have a viral infection I will pretty much carry on with everything I normally eat. I hate popcorn even if I'm well