Aug. 16, 2011 -- Obese people who are otherwise healthy live as long as normal-weight people, new research from Canada suggests.
Some obese but healthy people actually are less likely to die of heart problems than normal-weight people who have some medical conditions, the researchers found.
"You shouldn't just look at body weight alone," says researcher Jennifer Kuk, PhD, assistant professor of kinesiology and health science at York University in Toronto.
"A healthy lifestyle, including being physically active and eating a healthy diet, is probably more important than your body weight and focusing on weight loss, if you are otherwise healthy," she tells WebMD.
Kuk and her colleagues used a new tool that helps identify which people would benefit from weight loss and from weight loss surgery. Called the Edmonton Obesity Staging System (EOSS), it grades or stages obese people depending on whether they have diseases such as heart disease or cancer.
The study is published in Applied Physiology, Nutrition and Metabolism.
Obesity vs. Normal Weight
The researchers followed 6,000 obese Americans for 16 years, from 1987 to 2001. They compared their risk of dying from any cause or from heart disease with the risks of death for more than 23,000 normal-weight people.
For this study, they modified the EOSS, which normally includes stages zero to 4, to zero to 3.
The stages are based on traditional measurements such as body mass index (BMI). A BMI of 30 or above is termed obese.
The system also takes into account clinical measurements such as high blood pressure and diabetes.
Those obese people in stages 2 or 3, who had moderate to severe co-existing medical conditions, were 1.6 to 1.7 times as likely as the normal-weight people to die from any cause during the follow-up.
They were more than two times as likely to die of a cardiovascular cause.
However, those in stage 0 or 1 who had mild or no other coexisting medical conditions were at a similar risk of death as normal-weight people. Their risk of death from heart disease was slightly lower than normal-weight people. Those in stage 0 and stage 1, Kuk tells WebMD, are physically active and eat well, including lots of fruits and vegetables. They also tend to feel fine and may not be interested in losing weight.
The average BMI of those in stages 0 and 1 was 33. Those in stage 2 had an average BMI of 33.4. Those in stage 3 had an average BMI of 33.5
The message, she cautions, is not that you can become as heavy as you want without consequences. The more you gain, the more likely you are to develop the conditions of those in the higher stage groups, she tells WebMD.
"Weight confers different risks for different people," says Kelly Brownell, PhD, director of The Rudd Center for Food Policy and Obesity at Yale University.
He reviewed the study findings but was not involved in the study.
The fundamental message, he says, is that people should eat healthy food and exercise regularly, even if it doesn't affect their weight.
It is not surprising, he says, that some obese people seem not to be affected adversely. "When you unleash a toxin on the population -- for example, tobacco -- there is a massive increase in disease," he says. Yet, not everyone who smokes gets lung cancer or other lung problems.
Likewise, obesity affects people differently, he says. Some will develop problems such as diabetes or high blood pressure, while others will not, he tells WebMD.
Robert Kushner, MD, medical director of the Center for Lifestyle Medicine at Northwestern Memorial Hospital, Chicago, agrees. He also reviewed the paper for WebMD. He was a co-author of a 2009 report describing the new system but did not help develop it, he says.
The message, he says, is "Yes, you should know what your BMI is. In general, the higher your BMI the more fat you have and the higher your risk of developing medical problems." However, there are exceptions.
Those most likely to be obese and stay in the 0 or 1 stage, he says, are those with a high level of fitness.
Those in these lower stages, he says, were not only fitter but ate more healthfully. "Although biology probably has something to do with it, your behaviors will guide, in large part, the outcome of whether you are going to develop illness or not, based on your BMI."