Being severely overweight can increase your risk of dying early by as much as 24 percent. And this fact remains true even if you don't have any other identified health problems. This finding, which comes from researchers affiliated with Mount Sinai Hospital's Lunenfeld-Tanenbaum Research Institute in Toronto, Canada, disputes an earlier premise that it's possible to be both obese and healthy.

The Healthy Obesity Myth

"There has been a lot of controversy about metabolically healthy obesity," explains Ravi Retnakaran, MD, an endocrinologist who co-authored the Mount Sinai (Toronto) study, which appeared in the Annals of Internal Medicine in December 2013. He says that "healthy obesity" refers to people who have a BMI of 30 or higher without elevated blood pressure, cholesterol, and blood sugar levels. But Retnakaran speculates that obesity without such other health issues is really just a myth: He points out that significantly overweight people whose health measures are in the normal range may just not have progressed to the point of having quantifiable metabolic issues yet, but he says that over time, these health issues are likely to arise.

Exploring the Data

To come to this conclusion, Retnakaran and his colleagues looked at the results of eight studies that followed a total of 61,000 patients to see the relationships that exist between weight, metabolic factors, longevity, and cardiac problems.

The researchers sorted the data into normal, overweight, and obese groups, then further stratified the information into two subsets: metabolically healthy and metabolically unhealthy. What they found is that in each weight category, the metabolically unhealthy group had a higher risk of disease than the healthy group. But when it came to the obese group whose members were in good metabolic health, the researchers found that they were still at higher risk of dying early and/or experiencing cardiovascular events than people who weighed less.

Timing Matters

While these findings conflict with results from some earlier studies, Retnakaran says that the other studies may not have followed the participants for long enough for the health issues to set in.

"Cardiovascular disease doesn't happen overnight," he explains, adding that it may take a while for the disease to progress enough for the symptoms to show up. However, when you follow people over an extended period, he says that it becomes clearer that obesity does ultimately cause health to decline.

An Important Public Health Message

"I think there is a vital public health message here," Retnakaran stresses. "It's really important for people to strive to maintain or achieve a healthy weight, and the absence of metabolic abnormalities at a given weight over normal doesn't necessarily mean that you don't have an increased risk of mortality and cardiovascular health."

What this means for you is that if you're overweight, it's necessary to adopt a good diet and exercise plan regardless of your risk factors. Doing so may end up helping you live a longer and healthier life.

Ravi Retnakaran, MD, reviewed this article.

Sources

Ravi Retnakaran, MD, Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada, phone interview 11 December 2013. http://www.lunenfeld.ca/researchers/retnakaran

Caroline K. Kramer, MD, PhD; Bernard Zinman, CM, MD; and Ravi Retnakaran, MD. "Are Metabolically Healthy Overweight and Obesity Benign Conditions? A Systematic Review and Meta-analysis." Ann Intern Med. 159(11)(2013):758-769. doi:10.7326/0003-4819-159-11-201312030-00008.Web. Accessed 13 December 2013.
http://annals.org/article.aspx?articleid=1784291

"'Healthy Obesity' is a Myth, say Researchers at Mount Sinai Hospital," Mount Sinai Hospital Lunenfeld-Tanenbaum Research Institute, accessed 10 December 2013. http://research.lunenfeld.ca/rssnews/?page=2038