I haven't listened in a long time, but it was a vegan freak podcast that finally convinced me to get serious about trying to eat healthy.  They don't normally talk about that stuff, but the guy had just found out he had diabetes, and his description of his diet and lifestyle (including how he thought each of those was much healthier than the average person's) sounded WAY too familiar for me... it really helped me get away from processed crap and lots of sugar and fat and toward more fresh produce and whole grains.