I just came across this video of someone who was on a whole food plant based for 2.5 years and returned to a processed vegan diet.
youtube.com/watch?v=vHeQNNS...
By examining his blood test results it shows that a processed vegan diet has a risk of diabetes. Cholesterol is higher as well. Obviously this is just an anecdote, I wish there was a study!
Whatever I think anyone transitioning to a vegan diet should seriously consider it as - a transition - and so learn the benefits of a whole-food plant-based diet.