Walking will make you live longer.
This message has been reiterated in a recent paper (full copy here) where the authors declare "plain wrong" the conventional model that see dietary saturated fats clogging arteries.
Saturated fat does not clog the arteries - the cardiologists authoring the paper say - because coronary heart disease is a chronic inflammatory condition.
Yes preventing the development of atherosclerosis is important but to avoid myocardial infarction it is much more important preventing atherosclerotic plaques rupture.
Here is where walking and dietary changes like increasing good oils (mainly extra virgin olive oil), nuts, fish and vegetables can demonstrate how lifestyle changes and real food are the best medicine.