The trouble is that people who have no problems to do this ... are the ones at risk for anorexia. They lack the instincts that make the rest of us safe from that particular hell.
The thing that makes anorexia possible (among other things) is you being able to ignore hunger. Healthy organism will instinctively eat when hungry or missing something. The instincts takes over, body produces hormones to override behavior and diet ends.
I think a lot of people talking past each other on this topic are really just disagreeing about what healthy will power actually is. To be specific, comments along the lines of "it's not my/their fault, it's the fault of our environment, and the availability of unhealthy food".
I think this is just having an unhealthy will. I think this is also the whole divide on things like ozempic - some people view it as enabling people to have unhealthy will power. Other people view it as the only way someone can have healthy weight. I don't think either party is wrong, I think they are just talking past eachother.