I finally got around to reading a book by my hero Albert Stunkard M.D., called "The Pain of Obesity" that was published in 1976, before I was born.  Dr. Stunkard died a few years ago. When he wrote this book he was 50 years old but he continued to research obesity for many years after that.
He was a psychiatrist and he trained when Freudian psychoanalysis dominated psychiatry. In those days all psychiatrists had to be psychoanalyzed themselves. That takes years of frequent visits to the analyst which he dutifully did. But Dr. Stunkard wanted to be a scientist and Freudian psychotherapy could not be objectively measured and was impossible to study. He gave short shrift to all that after his training was over and today this Freudian business is gone from psychiatry except for historical interest. But Dr. Stunkard in this book was still using the term neurosis which was a Freudian thing that is no longer listed in the diagnostic manual of mental diseases, and he was still treating patients with psychotherapy that involved frequent visits, sometimes more than twice a week, for years. But he was clear eyed enough to say that there were as many psychotherapies, whatever the underpinning theory, as there were psychotherapists.
How he wound up being an obesity scientist was partly by accident and partly because it was poorly understood and even more poorly treated and it had an easy, objective accurate way to be measured - just stand on the scale.
His first scientific endeavor was the glucostatic theory. This looked promising as an objective way to measure hunger and presumably the cause of obesity. It was seen that if your blood sugar went down you got hungry. When you ate your sugar went back up and you stopped eating. But after many years of ingenious experiments and volumes of publications it turned out to be way more complicated and useless.
Then he discovered night eating from interviews with patients. This is really a thing but also pretty useless for understanding obesity although I think he missed or at least doesn't mention that night eating might represent the embarrassment of obesity which is the otherwise overarching theme of this book.
His next adventure in this autobiographical odyssey arose from an interesting story of an army general who was dismayed that so many of his troops were fat. So he gave the order that whoever was fat had 30 days to lose the weight or be dishonorably discharged. The army is a totalitarian state but in the end it is controlled by the civilian government and so the general couldn't do that. A study done during a brief contract Dr. Stunkard had with the army showed that the obese men didn't have any emotional diseases to any degree greater than non-obese men, especially considering the disdain that they have to contend with in their social interactions. 
It was widely felt that obesity is somehow an emotional disorder. The Freudian explanation of obesity was that it was an "infantilizing disorder" because obese people have baby faces and that is their unconscious desire.  But after studies of dieting and depression, binge eating, physical activity, social class, disturbances of body image and long treatments with psychotherapy Dr. Stunkard was no closer to a synthesis of obesity or it's treatment.
One case study was Herbert Marx, who was treated by Dr. Stunkard over 3 and a half years and discussed over several chapters of this book in great detail. After many cycles of losing and regaining tons of weight, Mr. Marx finally ended up permanently losing all of his excess weight and living happily ever after. But he must have been the only one treated by psychotherapy to finally succeed and Dr. Stunkard is quick to admit that this is no reasonable way to fix the problem.
On page 187 while discussing the failures of medicine as well as popular fads for fixing obesity he says, "...and even (defying the laws of thermodynamics), a diet in which we are told 'calories don't count.'" Remember that?
The last chapter tells of the possible success of behavioral therapy in treating obesity. It seemed to be helpful for treating anorexia nervosa, which is indeed serious psychpathology. Simply by training obese patients to do various ritual behaviors - taking a long time to eat, counting spoonfuls, keeping careful records of when, what and how much they ate... they were able to achieve more average weight loss than any other known method. The interesting thing they also found was that though the average weight loss was greater the spread between those who lost a lot and those who didn't lose any weight or gained weight was greater with this behavioral therapy. This type of weight loss method has not panned out in the long run.
In his many years of talking to obese patients Albert Stunkard found that everybody hates fat people, and even fat people hate fat people and they even hate themselves. That's the pain of obesity.