No, no--it's not that weight restoration cures everything! Because my life right now is an obvious example that this isn't exactly true. I would never say that weight gain isn't necessary, just that it's the necessary first step towards a meaningful recovery. If weight gain "cured" anorexia, then there wouldn't be the tremendously high rates of relapse that we see. The difficulty with weight gain is consequently keeping the weight on for long enough to get physically used to your new body and to begin the mental healing process.
But I digress.
The reason I find this article so incredibly interesting is how it managed to examine the relationship between somatic factors (ie, weight) and psychological factors (ie, ED psychopathology). Usually, the mind/body connection is seen as something very heebie-jeebie and New Age-ish, an idea sprung from the mind of a few pot-smoking hippies reeking of patchouli. But the brain was connected to the rest of the body- at least the last time I checked. The brain is an organ, just like your heart or your liver.
The mind/body separation in Western culture has been around for hundreds of years and has resulted in some rather interesting separations in medicine. The need for mental health parity is one of them, although that could also be interpreted the machinations of a bunch of cheap-ass insurance companies. With eating disorders, the assumption was that the ED thinking caused the behaviors that caused malnutrition and weight loss. It was a one way street. Although this is somewhat true (most people with AN don't start out malnourished no matter how catastrophically they end up that way), the opposite is also true. Low weight can cause ED thinking, which causes ED behaviors and a further increase in malnutrition, and I think that's what they call The Perfect Storm.
The body and mind aren't separate. Your brain uses approximately one quarter of the calories you eat (500/day) and is essentially a glucose hog. If you starve your body, you starve your brain. I managed to shrug many of the physical effects of anorexia off, but the cognitive effects really got to me. The knowledge that I can't preferentially shunt calories to my brain has helped me resist urges to restrict. I know I'm not the next Einstein, but my job requires a lot of intense, deep thinking, and anorexia would grind that to a halt. I don't miss being caught in the circular ED thinking, worry about what I ate, what I will eat, what I might eat, and exercise and fat grams and everything. If I delay my meals or snacks for any length of time, I notice a return of the anxiety and ED thinking, even if I don't notice a difference in my hunger levels.
It seems odd to think that something as simple (though fraught with challenges for those of us with ED) as eating could improve state of mind. It's not a cure, but it should stop being so surprising to so many people.
(An interesting note: the one area of psychopathology that didn't improve with weight gain was perfectionism, which emphasizes how this is a long-standing personality feature of many with EDs rather than limited to the time when one is acutely ill with ED.)