Sure, being generally unhealthy can have a significant effect, but that doesn’t mean it’s the main culprit. It’s great that you have the motivation to do these things, but not everyone does, no matter what the cause of depression is, and even if the resulting lack of physical activity compounds the negative effects.

Anyway, it seems that we agree that it’s not only caused by individuals actively choosing to be unhealthy.

(I’m assuming you’re being hyperbolic with that last sentence)