Is push up and crunches ok after breakfast?

Felix Y.
Honestly yeah, don't worry too much about that. You might get a bit of a cramp doing it that way but there really isn't anything awful that'll happen.
Enola Y.
Yes but if you are not used to doing them or you overdo it you could make yourself sick. I find it is better to do a quick workout before breakfast or a big workout about an hour or more after breakfast.