Should Obesity be Classified as a Disease?

The American Medical Association, last month at their AGM, voted to classify obesity as a disease, and "at a stroke, a third of the US population became diseased." The question is, should just being fat be automatically enough to classify someone as being sick and needing medical attention? The BBC reports that;
The AMA president, Ardis Hoven, says the new designation will increase the focus on obesity treatment and prevention, and in doing so help medical professionals deal with the increasingly complex health problems associated with being overweight or obese.

Though obesity has been a health issue in the public eye for decades, doctors are not always equipped or prepared to help patients treat and prevent obesity-related illnesses.

So should obesity on its own be a disease? Weighing in on the issue, a FB page shared the photo and caption below;

These two pictures show body scans of two women approximately the same age and height. The one on the left weighs 113 kg (250 lbs), while the one on the right weighs 54 kg (120 lbs). Accumulated adipose tissue is not the only difference between the two; the obese woman has an enlarged heart and her lungs are somewhat restricted.

Obesity has recently been declared a disease by the American Medical Association. While this does not have any legal ramifications, it may encourage doctors and insurance companies to take more steps in treating and preventing obesity. However, many disagree with the AMA's definition, citing that obesity is a complex issue with multiple causes and treatment options.

Obesity is defined as having a body mass index over 30 kg/m^2. It greatly increases the risk of Type 2 diabetes, heart disease, and osteoarthritis.