Hey Taft –
I like to make sure that my breathing is pretty much recovered from the previous set in order to get the most out of the next. Unless you are doing metabolic type training I see no point in going into a set with oxygen debt.
As far as meals before training when it comes to training earlier in the day the main thing that I think is important is that you are properly hydrated, in all honesty we are more so operating off of food from the previous day. Going into training on one meal is fine!