I eat lots of sugar (and pizza), but I have very low bodyfat. It's about how much you eat (food with sugar often has lots of calories).

Just track how much you eat, then you can be lazy with food preparation (I am too). If you feel hungry and need something filling, eat some protein.

Tracking calories can be annoying at first, but after doing it for a couple of week you'll get intuition and you won't need an app anymore.