I'm a 
big fan of Dr. Anthony Lim. I saw him speak at a 2016 McDougall weekend, and was completely impressed with his communication skills and humble manner. (Dr. Lim is also a strong Christian who graciously endorsed my book!)
Check out Dr. Lim's 11-minute interview from 2017, For many years, he was convinced that "carbs were bad." He was a huge advocate of Paleo type diets during his medical training and early residency, but changed his point of view and became a passionate advocate of whole food, plant-based (WFPB) eating - in just one day!
He also points out the mistakes that people make during their transition to WFPB eating.
Dr. Lim now serves to help people at the TrueNorth facility in Santa Rosa, and is also the medical director of the McDougall Program.
Humble yourselves before the Lord, and he will lift you up in honor.
(James 4:10, NLT)