Being hungry while playing makes me tilt for small things. I can't really focus, and make mistakes, which tiltes me, which makes me angry, and so on... Just the same as being tired, but the difference is that you just need to go and eat for the first case, which is acceptable if you play cash, but have to wait the break in mtts. For the second case, well you should stop, and being tired means you will be in good shape not so soon.