Always empty, 3 or 4 hours without eating. I don't think the difference is as extreme as is made out, you're still going to feel something at least even if you've just eaten. I think in my experience of trial and error eating before just dulls the effects a lot. You don't get a nice kava uplift, just a creeping calmness. I prefer a big hit on an empty stomach, get some KL's working for me!