I usually eat light and healthy, a few hours before dosing. Because if I have too much food in my stomach, it will decrease the effects along with taking longer to start kicking in, and if I don't eat all day or am really hungry when I take it, I can get nauseous, or at least uncomfortable. Sometimes the hunger even persists into the experience, but I still mentally won't want to eat which makes it really distracting and annoying. So not hungry but not full. Like I said for me, a light, HEALTHY meal a couple of hours beforehand and I'm good.
As far as the original question... Yeah I'd say 3 months is a safe bet. I know one guy who did it once a month and at about the 6 month/6th roll mark he said it started to lose it's magic and he had to wait quite awhile for it to come back... over a year. And I'd say he's lucky because for many people it never comes back.