Many experts disagree.

Right?
I think I am guilty of cherry picking data I like and pasting it in the forum.
Discourse is almost dead. 
I go ahead and like the posts by my HO pals and I might get pedantic and list all the anecdotes and exceptions I can think of to disagree with someone posting data I don’t like.
Have I changed my mind about anything since I started to post on Chowhound in 2003?
Why yes, I have!
I thought I hated banh mi based on Chowhounds raving about Rose’s Banh Mi. I rarely throw food in the trash and I threw that Banh Mi into the trash.
I tried a couple more over the next 15 years, and it turns out, I like some Bahn Mi, just not Rose’s mushy pre-made Banh Mi.
I am also now open to eating all types of baklava.
I seek out more French restaurants now. I avoided French food 20 years ago because so many people seemed obsessed with it.
Have I changed my mind on diet , regimens, the Mediterranean diet, the Zone?
Not really. I lost about 20 lbs over 2004, with a kick start in Greece during the Olympics. I kept my BMI around 24 to 25 and my weight around 145-150 for 2 years. I was pescatarian for 1 of those 2 years, but I was craving chicken soup the whole time. It wasn’t sustainable for me. I haven’t been able to stick to a pescatarian diet for more than 4 days in a row since then. The first 15 lbs of weight crept on over first 6 months I went back to an omnivorous diet, and coincided with me starting to meet up with Toronto Chowhounds for group dinners once or twice a month, and Chowhound being purchased by CBS, becoming more addictive to chat and fight, relative to the old Blue and White board .
The Chowhound restaurant meetups turned into restaurant meetups as well as potlucks, cake days and waffle days a couple weekends a month.
In 2015, I backed out of group home cooking meetups partly because I couldn’t keep a healthy regimen and I couldn’t. I threw myself into my ski club and hiking, and changed my pattern so there was cooking focused socials and feasting.
Most recently, since I haven’t really returned to indoor dining apart from one indoor meal before the opera last week, my one Toronto Chowhound friend for on a 10 to 14 km bakery walking tour a couple times a year. 
I keep trying to lose weight. I do use BMI, and scales, and I measured my waist and hips last night.
I understand not believing in BMI. I understand BMI not working for many body types. I understand BMI not working for very athletic or muscular people.
I also know, being white and also small-boned, I have a whole set of medical issues that are more likely to happen to me. My friends who are South Asian, Black, Asian, First Nations and/ or mixed race have sets of medical issues that might happen to them.
BMI is a tool that doesn’t work for everyone. That’s all.