The idea that people can be both obese and healthy is called into question by a new study that finds that, at least over the long term, obesity may confer a small increased risk of death.
In the study, people who were obese but did not have metabolic problems — meaning their blood pressure, cholesterol, blood sugar and other measures of metabolic health were normal — were still 24 percent more likely to experience a heart problem, such as a heart attack, or to die over a 10-year period than normal-weight people who also had no metabolic problems.
The results “demonstrate that there is no ‘healthy’ pattern of obesity,” said the researchers, from Mount Sinai Hospital in Toronto. Their study was published in the journal Annals of Internal Medicine.
In an editorial accompanying the study, James Hill and Holly Wyatt, of the University of Colorado, said the findings are consistent with the idea that obesity itself is a disease, a controversial position that the American Medical Association supported this year.
However, some experts disagree with the researchers’ conclusions. Pieter Cohen, an assistant professor of medicine at Harvard Medical School, stressed that the effects of metabolic conditions such as high blood pressure and high cholesterol are “much more important for long-term heart health than one’s weight.”
Research on whether people can be obese and healthy has had contradictory results. A study published this year found that people who are overweight actually live longer than people of normal weight.
In the new study, the researchers analyzed information from eight previously published studies involving more than 61,000 people, most of whom were in their 40s and 50s. Just how long researchers followed participants varied depending on the study, from three to 30 years. About 9 percent of participants were obese but metabolically healthy.
Overall, people who were metabolically unhealthy — with conditions such as high blood pressure, high cholesterol and diabetes — were at increased risk of heart problems or death during the study period, regardless of their weight.
When the researchers considered only studies that followed participants for at least 10 years, they found that, even with no metabolic problems, obese people were still at increased risk for heart problems or death during the study period.
Cohen said he would have interpreted the results differently. He pointed out that, according to the study data, just one out of 140 “healthy” obese people would be expected to die or have a heart problem over a 10-year period. “I would look at the glass completely full, in that if your metabolic panel is great, obesity itself confers an extremely small risk of heart disease,” Cohen said.
The researchers said that, when applied to the worldwide population, their findings translate to 1.4 million deaths or heart problems over a decade.
Cohen said that while the researchers followed participants for years, information about participants’ metabolic status was collected just once. So even among the 1 in 140 healthy obese who were at increased risk of death or heart problems, it’s unclear if that risk should be attributed to obesity itself or to a worsening metabolic condition that was not captured by the study, Cohen said.
The study was not able to take into account how much physical activity participants engaged in, a factor that might have also affected their risk of death.
However, Cohen said that because obesity can increase the risk of such joint problems as damage to the hips and knees, it is still advisable for obese people to lose weight even if they are metabolically healthy.