A few links brought me to a post Ragen Chastain wrote for her blog Dances With Fat in 2012 in which she links to a bunch of studies on the lack of connection between obesity and disease. I'll leave the links in her article and summarize her summaries. There are studies on:
* Weight loss diets do not lead to sustained weight loss and do not lead to a significant health improvements. Therefore there is no reason to ask people to endure them.
* Healthy lifestyle habits are associated with a significant increase in health regardless of body mass index. It's not the obesity, it's the fitness.
* If a person is cardiorespiratorily fit there is very little difference in mortality between those of normal weight and obese. There is a marked difference between the fit and unfit, even for those of a normal weight.
* Doctors tend to view obese patients as ugly and noncompliant and some add in sloppy and lazy.
A patient tagged as noncompliant will have a much harder time getting proper treatment for other issues and getting proper insurance payment.