The former is a much easier transition for many. Indeed most go the former route rather than the latter.
There was some Iranian sect which was vegan and survived fine because they didn't wash their vegetables much. They raised their vegetables using human manure which contained B12 plus, since they didn't wash the veg much, they also ate insects along with the leaves.
Yes, I heard about iranian guys. Actually used this same argument during my vegan times. I would like to know more about it, searching the internet didn't provide any roots of this story for me. Besides, it is sect, who know how long people stay there or how healthy they are? If you have more information on this, it would be interesting to see.
For me route number one doesn't work, can't tolerate carbs, cause IBS, especially fructose and even most of the raw vegetable. Cooked or fermented are mostly fine. After switching to low carb noticed significant improvement, too short yet to draw conclusions, but cooked fat seems fine, use a lot of rendered lard.
It is individualistic, somebody else might find vegan route easier and somebody can go cold turkey and be just fine.
