I think you should definitely be getting it in on a 'rest day' as this is when your body is recovering and repairing itself, in other words building muscle!
I consume about the same amounts of everything every day whether I'm working out or not. I don't think it makes much difference when you have things, personally. I don't believe your body can tell you ate such and such at 5pm on a Wednesday or 3am on a Friday, over the week it won't make any difference. So, whatever you do be consistent.