Assuming you're talking about Dr. Naiman - he's been my doctor for 15 years. He is the nicest doctor I've ever had and was nice and very respectful when I was over 300 pounds, unlike some doctors I've had in the past.
He is into following the body builders, and I don't get the scowling pictures either. I took a picture of him in the clinic once, and he definitely smiled!
He originally put me on low carb/high fat and he was really into the low carb diet back then around 2007. I did well and lost some weight, but I settled somewhere around 250 then after several years started gaining again. At some point, I think around 2018, he switch to high protein and tried to talk me into it. I wasn't having it and felt he was all wrong. I finally decided to try it and finally hit goal weight in my mid-50s (I mean I'm age 57). I did it with his high protein diet plus IF (I did do low carb/high fat plus IF when Jason Fung's book hit the market, somewhere around 2016, something like that, but that was just a roller coaster of loss gain for me).
If you're interested at all, Dr. Ted Naiman's YouTube videos are more representative of his actual personality. Honestly, it was a hard sell for me from the get-go. This entire time, I thought I was old enough to be his mother! He is only about 7 years younger than me, I had no idea. The first time I saw him, he looked like he was maybe 14, and all I could think was, "Oh, I don't think so!" But he was obviously really bright and very convincing, even though he has a very calm and relaxed demeanor.
I used to post his Burn Fat not Sugar videos on Low Carb Friends, if you were back on that forum a long time ago.
Anyway, it has been a long road, and finally, 15 years later after he became my doctor, I have finally lost the weight. Down 160 pounds, most of it since July 2019.
I once told him I was so mad at him for not coming up with high protein sooner - he just looked down and said, "I know." Ugh, I felt so bad that I said that!