I think quality food is a no-brainer, but convenience eating, like you calculated, is an easy bad habit to develop. If you're deliberate about when, where, and why you're eating out, than it seems unlikely to be a problem though.

I'm curious, what role does health insurance play in Germany? I'm been curious about the prospect of at least temporarily living in Germany (from Canada), but don't have a great sense of that yet. Here we have socialized medical, but you'd get insurance to cover out of country emergencies, regular cost of drugs, and dental, among other things.