Aug. 15, 2011 -- Researchers are testing a new tool that helps doctors figure out which overweight and obese patients are most in need of medical treatment and which are likely to remain healthy, even at very large sizes.
The tool, called the Edmonton Obesity Staging System (EOSS), was developed by researchers in Canada, a country where people who need weight loss surgery can linger for years on waiting lists.
"When you have a waiting list, you try to think about how you prioritize people on that waiting list," says study researcher Arya M. Sharma, MD, PhD, professor and chairman of obesity research and management at the University of Alberta, in Edmonton, Canada, "Who do you see first?"
"So we thought, maybe take the heaviest patients first because they might be the people who are sickest," Sharma tells WebMD. "But when we looked at that closely, we found that that isn't always true."
Doctors call this the obesity paradox.
While obesity increases the risk for a host of serious health problems, including heart disease, diabetes, arthritis, and cancer, carrying around a few extra pounds can sometimes be protective.
In a study published in 2007 in The Journal of the American Medical Association, CDC researchers found that overweight people had a decreased risk of dying compared to people who were either underweight or very obese.
"We found that in terms of excess deaths, that is, deaths above what you would predict if the person had been normal weight, in the overweight category, there were fewer deaths than you would have predicted, that is, overweight was some way associated with lower mortality," says Katherine M. Flegal, PhD, senior research scientist at the National Center for Health Statistics.
"There's a fairly large literature now suggesting that in a lot of situations, if you have a medical condition, your survival is better at a slightly higher weight," she says.
"Body weight is not the strongest risk factor for a lot of conditions," Flegal says. "It's just one of many risk factors."
Other experts agree.
Joel Zonszein, MD, an endocrinologist and professor of clinical medicine at the Albert Einstein College of Medicine in New York, says that body mass index (BMI), a measure that takes into account both a person's height and weight, alone doesn't say very much about a person's overall health.
"BMI is simple, but it doesn't tell the whole story," he says.