Since you’re talking about yourself, „Meine Essgewohnheiten“ would be even better.

D ie Essgewohnheiten

„Obwohl ich etwas Süßes essen mag“ is grammatically correct, but it means „Although I want/would like to eat sweet things“ instead of just „I like sweet things“ and it also kind of means that you want to eat something sweet right now.

Letzte Nacht habe ich einen Schokoladeriegel gegessen.

„Es“ would also be okay, but then you’d be more generally speaking about eating sweet stuff instead of talking about this specific chocolate bar.

E r war sehr lecker, aber das war nicht gut für meine n Körper, weil Schokolade dick macht.

„Er“ since it is „der Schokoriegel“

Side note: „Schokoladenriegel“ gets abbreviated to just „Schokoriegel“ very, very often.

E r macht dick, da e r Zucker enthält.