> How do I REALLY do something about this other than a few pretentious yet barely discomforting lifestyle changes and the odd empassioned few sentences at dinner parties?

I would recommend the Mr. Money Mustache blog. While its premise is early retirement/financial independence, the author writes extensively about lifestyle design. His actual (self-stated) goal is to save humans from destroying themselves.

The prescriptions sound drastic at first (ride a bike for any trip under 10 miles?!) but it turns out they also make you healthier and richer.