the hunger is part of it, roisin. punkin didn't use to be an endless eater either, but he sure is now. they don't use their food as efficiently when they're unregulated, apparently.
you might see higher numbers from the pizza scavenging, but it will clear. there was probably a lot of carbs & straight out sugar in it, but just hold your dose and don't be surprised if it goes up. overall though, his numbers are at a good point!
these things happen - the worst is that kitties like their dry food - we joke about it being kitty crack! it makes their BG go up and stay up for awhile.