An infuriating conversation I just had

I just walked into the kitchen at 3:15 in the afternoon. My very diabetic dad has apparently gotten out one of the 30-carb Jimmy Dean breakfast bowls and cooked it for himself. (For those who don't know, a snack for a diabetic is 0 to 15 carbs.)
Me: Really?
Dad (in the other room in front of his desk): What?
Me: You thought you'd get out a 30-carb breakfast bowl and eat it at 3:30 in the afternoon?
Dad: Well, I guess not.
I paced around the kitchen a bit, trying to keep calm. Then I asked him the question that always comes up in moments like this.
Me: I just don't get why you can't read labels.
Him: Well, I figured you'd come in and find it, so no big deal.

Like, wtf? Does he think this is some kind of game? Does he think it's funny to waste food?