This is well worth the time, at least for someone like me that listens to podcasts at 2x speed. I think Joe Rogan hit it on the head that the biggest takeaway is the modern diet sucks.

Unfortunately, it isn't until more than 3 hours into a nearly 4 hour podcast that Dr. Kahn (vegan) admits he does not advocate tying to get all essential nutrients from food and that to be vegan, one must supplement. To me, this is the single biggest argument against being vegan.

Please do not misunderstand me. If someone wants to be vegan, that is their choice. Just don't tell me that it is for health reasons if it is impossible (or nearly impossible) to eat that way without supplementing or having severe deficiencies in B12, DHA, EPA, and other nutrients vital to health.

And, someone eating vegan properly and supplementing will be far healthier than someone eating the modern diet of the industrialized world. That does not make it optimal.

http://podcasts.joerogan.net/podcasts/chris-kresser-dr-joel-kahn