The struggle i have had is i have seen just as passionate vegans say they have all the studies to prove that their path improves all the numbers. And many of them are thriving in that lifestyle. Id like to see these opposing sides in the same room talking it out.
I also have read and experienced that for a number of people dropping carbs too low for an extended period lowers serotonin and they can become irritable or even angry.
Finally, his comment on getting cheap eggs, meat, etc…is frankly scary. The poisons in processed boxed foods are just as present in different forms in conventional animal farming. Bovine growth hormone and antibiotic laced feed does just as much harm as sugar and gmo grains. The quality of the food is just as important as eating cleaner unprocessed foods weather carb, fat, or protein.