But one thing that really helps with weight loss is learning to control impulses and that means controlling overeating. I did not start yoga for weight loss, but have lost about 8-10 pounds over the last year, just in that I am more in tune with my body and stop eating when I am full. I still eat mostly what I want, but have always had a pretty healthy, plant-intensive diet.
For people with eating disorders, tendencies to overeat, etc. the common wisdom is that learning to handle the "problem" of difficulty in a pose, eventually means you gain more ability to notice when you are eating because of anxiety or that you are doing something harmful to your body (eating the whole pan of brownies) and then being ABLE to STOP.
It can take some time, like anything, but starting to feel better about your body's ability to do things and feeling more flexible and strong can go a long way towards feeling better about yourself. There is a union between the emotions, the spirit, and the body that is accessed while practicing yoga. Vedic theory talks about personal challenges are maintained in certain parts of the body. By accessing and mobilizing those areas, we can start to explore why we have those personal challenges. For example, I became more flexible in my hamstrings and a large part of my anxiety issues went away.