That statement is addressing the wrong issue. Yes, the personal discipline isn't there - but WHY? I consider myself to be pretty disciplined when it comes to getting showered in the morning and going to work. But someone with severe depression or other illnesses can't even get out of bed. There's no point in looking at that person and saying, "s/he doesn't have personal discipline." The question is why not? Where did it go? That person may have had no problem much of their life, so what happened exactly?

To paraphrase Gary Taubes (I think?), that's like investigating an airline crash and concluding, "well, obviously the plane crashed because there was insufficient lift on the wings. Case closed." Well, duh, but there are many different factors and you have to figure them out if you want to avoid the same thing in the future. It could have been caused by human error, insufficient training or staffing, a multitude of mechanical failures, weather, etc.

In the case of dieting, it's like Zei said: we're told we're supposed to just ignore hunger, as if it doesn't wake you in the middle of the night, as if it isn't distracting you from your job, as if it doesn't make you dizzy, as if food doesn't start becoming an obsession. It's supposed to work this way. Our species wouldn't have survived if it didn't.

...until you eliminate (or at least minimize) grain and sugar intake. Eat a species-appropriate diet minus the addictive substances, and all of the sudden your "personal discipline" reappears. But LC is still seen as "dangerous", and you must eat your HeartHealthyWholeGrains and eat less meat, so let's blame a lack of discipline instead.