Having lost over 150lbs and kept most of it off for about a decade, I disagree. Knowledge about nutrition[0] is insufficient. The only reason I was able to do this at all was that I was in a very low-stress period of my life at the start and after that I have had to put a whole lot of effort into not ballooning up again, to the extent that my behavior patterns were described as an eating disorder.
I am hardly unique in this. I would argue that to lose and keep off this kind of weight without chemical assistance (good fucking luck getting a doctor to help there) pretty much necessitates the development of an eating disorder. It takes over a significant portion of your life and is no fucking fun at all.
Give me an apatite pill any day.
[0] this is without even mentioning how difficult it is to find information on nutrition that isn't complete bullshit pushed by people selling fads.