For me, the transition was pretty easy. But I made the change because I feel that SAD was destroying my health and quality of life. I've always been normal weight (slender-ish) but I developed an autoimmune disease. Once I read enough to link autoimmune diseases to leaky gut vis a vis grains/grain materials, it was all over but the crying.
Still, my 3 biggest challenges:
1) Getting enough iron. I mistakenly correlate protein sources as iron sources. Hmph. On SAD, I got my iron through fortified sources. Now, I have had to adjust my PB diet to almost require red meat once a day. Not always the easiest thing. I probably average 5 to 6 servings a week.
2) Snacks. I don't eat fruit, but a little munchy here and there would be nice. I think I eat too many pork rinds as a result. I've taken to eating a full-size carrot once or twice a day. Snacks on a recent 2k mile road trip were difficult.
3) Cost. I live alone and I make a decent living but I think this WOE would be cost prohibitive if I had a family and/or I was on a more meager budget.
Because if you didn't know, of that is life made: only of moments; Don't lose the now.