Listened to a recent interview of RB, and he was talking about eating in the astral as one of those anomalies that can help you determine that you are projecting. His example was along the lines of:

let's say you find yourself at a bar with a mug of beer and a bagel in front of you. You take a bite and a sip and put the food / drink down. Then you look at it and see that the bagel no longer has a bite in it and the beer glass is completely full again. Then you know you're in the astral.