Weight bias — blaming people who are obese for having the disease — also is a factor.
Primary care physicians often speak with patients who have obesity and tell them to eat less and exercise more, then that fails, said Dr. Fatima Cody Stanford, an obesity specialist, expert and Harvard University instructor. Then when the patient returns, the doctor just repeats the advice rather than treating it as a disease.
"People say 'oh they're just lazy or slothful'" about patients who have obesity, Stanford said, but no one would say that about patients with cancer or depression. For some reason, she said, people blame those with obesity for their disease, and many don't support medication because they see it as an "easy way out."
"We would never tell someone with diabetes who comes in with high blood sugar, 'Well, eat less and exercise more!' we'd treat their diabetes," Stanford said. Lifestyle changes are important and she recommends them to her patients, she said, but it's not enough by itself to treat people in many cases.
"Right now I see a barrier. These biases that are so strongly held continue to perpetuate so these patients don't get the treatment they need and they deserve," Stanford said.
Fox said it is not only doctors and insurers, but the patients and their families who have the bias and say, "I want to do it the natural way."
"We need to be thinking of it as a chronic condition, one you will need to manage for your whole life," Fox said, but she explained that when a doctor tells a patient and their family this, "you can see the gloom on the family's face, or they just don't believe you. ... Five years later that person is 100 pounds heavier. It doesn't go away."
Even when doctors do prescribe obesity medication, Stanford said, it's often with the goal of losing weight in the short term and then stopping to take the drug. This is wrong, she said, as those drugs are designed for people who will continue to take the medication indefinitely to lose the weight and keep it off.
Apovine said the idea that a weight-loss drug is for short-term use is science of the 1950s, but it persists.
"There are only a handful of us in this field, led by George Blackburn's work, that in the past few decades recognized obesity is a disease that needs to be treated," Apovine said. "We have finally starting to see some movement."
There is now an obesity medication certification program that has over 6,000 doctors and hopefully will soon be recognized by the American Board of Medical Specialties, she said.
"Eventually, we have to get to a tipping point, just like with addiction and alcoholism and depression. We don't consider those a moral failing now. We have to stop with the stigma of obesity," Apovine said. "We still look at a person walking down the street and say 'glutton' — eat less and exercise more. Once the perception of obesity is disease, everything will fall into place."
—By Edward McKinley, special to CNBC.com