Saw a few comments about this debate on Fathead FB. The 4 hours was non-starter for me, but someone posted in their comment:
"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."
Summed it up for me. Was there a good wrap-up at the end?