My apologies for being defensive. Many folks naively think bio-med research can take place without animal models. If there was an equally valid methodology, we'd use it; there just isn't.
I only watched a few mins of the Dr Greger vid, but he was IMO 'preaching to the choir' and ad libbing. There can be a 'PT Barnum' aspect of getting even te best science accepted / funded, but his demeanor was off-putting to me.
All that said, I certainly DO love my veggies, and have read and agree with M Pollan (Omnivore Dilemma). Really: eat the grain yourself or feed it to the cow and then eat the cow? I can certainly see the 'energy waste' and complications, but I will continue my omnivore ways, moderating my meat consumption but likely never giving it up entirely.
A slaughterhouse is a brutal place to say the least, but factory farming and mega-herbicide use with destructive tilling techniques is brutal in a quieter sort of way. Also consumes a lot of petrol. One of the last print editions of Newsweek I received had an article on the failing levels of durham wheat produced globally, while many still deny human influenced climate change....
IMO, the real problem is not so much <e>what is eaten, being mindful of relative amounts, but how many people need to be fed, and with America's focus on MORE as opposed to BETTER (and better for you) as the typical advertising thrust.