According to the American Medical Association, obesity is now officially a disease.

A highly preventable disease, but a disease nonetheless.

I think that's probably the right call. For many people, lung cancer is highly preventable -- just don't smoke -- but it would be weird not to call lung cancer a disease.

The decision wasn't without debate, though. In fact, the AMA's Council on Science and Public Health actually recommended against calling obesity a disease. The main issue revolves around using body mass index, or BMI, as a measure for obesity. A 5'11'' man who weighs 215 pounds is technically obese, but he may be fairly healthy and probably doesn't need to be treated aggressively. There was also a worry that calling obesity a disease might let people off the hook in trying to prevent it in the first place.

Ultimately, the AMA's House of Delegates ignored the council's recommendation, voting in favor of a resolution to recognize obesity as a disease.

Great news for these companies
In the past, there's been a distinct lack of interest in treating obesity. Doctors felt that it was mostly an aesthetic issue, so drugs to treat obesity had to be very safe. The severity of the disease is always a consideration in the acceptability of how severe side effects can be.

More recently, it's become clear that obesity is a risk factor for other issues including type 2 diabetes and high blood pressure, making prevention and treatment a higher priority.

Unfortunately, having Wyeth's Fen-Phen and Abbott Labs' Meridia pulled off the market because of side effect issues made many doctors wary of treatments. VIVUS (VVUS) got off to a very slow start, selling just $4.1 million of its obesity drug Qsymia in the first quarter, its second full quarter on the market.

The AMA's decision should shed light on the issue, stressing treatment. But I continue to think it's going to take time before doctors have enough experience prescribing Qsymia and Arena Pharmaceuticals (ARNA) and Eisai's Belviq that they're prescribing them to a majority of their obese patients. Clinical trial data is nice, but there's no substitute for real-life experience on a few select patients.

Perhaps more importantly, the AMA's decision could affect reimbursement for the drugs. VIVUS and Eisai are slowly gaining coverage from private insurersm, and an endorsement by the AMA certainly won't hurt their efforts. VIVUS is shooting for 50% coverage of people covered by private insurance by the end of the year  The AMA's endorsement may also affect government coverage. A bill was recently introduced into Congress that would provide coverage of obesity drugs by Medicare.

Orexigen (NASDAQ: OREX), the third player whose obesity drug could be approved next year, might be hitting the market at the perfect time, just as all the kinks are worked out. And if its drug Contrave is approved, it'll be the only one to have shown that it doesn't cause cardiovascular problems.