I was recently looking through the Canadian Guidelines on Obesity Management. This is a monster of a document: 24 chapters and over 100 pages. It's also infuriating. A few choice quotes:
"In addition, the medical profession is failing to counsel young, disease-free adults and those in lower socioeconomic groups" [to lose weight]. Because if you haven't yelled at healthy fat people, you just aren't doing your job!
"Overweight and obese people, especially those with binge-eating disorder, lack self-efficacy. Self-efficacy refers to confidence in one's ability to do what is required to produce the desired outcome." I was pretty angry when I read this. Just because I'm fat doesn't mean I am lacking in the ability to Get Things Done. So I went and looked at the abstracts for the three articles they use to reference this statement (1, 2, 3).
The first two articles refer specifically and only to weight self-efficacy -- which, apparently, is confidence in one's ability to do what is required in order to get to a socially-sanctioned weight. That is, fat people are pretty sure that they can't diet to become permanently thin. I would describe that as "fat people have a good grasp on reality" rather than "fat people have low self-efficacy".
The third article is the only one that refers to self-efficacy in general, and it finds that fat individuals with binge-eating disorder have lower self-efficacy than fat individuals without binge-eating disorder. Which, obviously, says nothing about fat people as a group.