My view is that being overweight is a result of overeating, obesity is then at the far end of that condition. Among eating disorders is the compulsion to eat more than one burns and obesity is the extreme result of that disorder. Therefore if obesity itself is a disease then those who are obese suffer from two separate diseases, one the result of the other. A great diagnosis for those who want a generous explanation as to why they are ruining their health.
I am of an age where I never had access to any diagnosis and labelling of any of my traits, as with pretty much all of my generation, and therefore we suffer from a shortage of opportunity to generate attention/sympathy and/or labelling and treatment/support. We are the unnamed underprivileged - anything people say about us now is that we are simply old...........hey, there we have it, old age is a disease. Get the NHS, social services, etc. onto this, there is a veritable epidemic going on.