Jason Fung is probably the world's leading research expert on obesity. If you want videos to watch on it, it starts and ends with this guy. He has done a ton of lectures and blogposts going back over a decade, and also has the stereotypical clickbaity YouTube videos.
He has surely dedicated a significant portion of his life to his own pet theories on obesity, but to consider him a well-regarded expert is very misleading.
He has quite a few claims that are just...ridiculous, and his pop science books have some serious flaws (as reported by actual experts).
https://www.youtube.com/watch?v=YpllomiDMX0