Night and day difference for me. 4-5 hours and it hits like a truck, less time not so much. I've had some kava after a large meal before and felt virtually zero effects from a dose that would've normally had me cross-eyed.
If I don’t eat small amounts with kava it can kill the buzz, whether too much or too little. But the thing that bothers me most is being full and trying to drink kava. Anything before that isn’t a huge deal.
Big difference with an empty stomach. However, once it hits and is close to it's peak, eating a meal often increases and prolongs it. Timing on that is pretty critical though.