well metabolic damage is real although I do laugh when I hear that EVERY SINGLE BB COMPETITOR HAS IT lolz
as someone who literally starved herself for decades, I did actually have some serious metabolic damage. Didn't require someone with a PhD in nutrition to tell me that, or to tell me what to do to fix it. Eat. More. Gradually. Adapt.
It's what humans do.
Won't judge the vid in the OP although must say Layne Norton's vids are pretty good. It's not broscience. The fitness/BB industry is where the haha's come into it a bit .. not the actual concept of MD.