By Alan Mozes



(HealthDay)

HealthDay ReporterTUESDAY, May 10, 2016 (HealthDay News) -- Obesity may not cut your life short after all, a new study suggests.

Danish researchers report that the risk that an obese man or woman will die prematurely has dropped dramatically over the last 40 years.

How dramatically? According to their analysis, the 30 percent greater risk of dying early from any cause found back in the 1970s has virtually disappeared.

Translation: The researchers said that the risk of dying early for any reason is now the same among obese individuals as it is among normal-weight individuals.

Not only that, but having a body mass index (BMI) of 27, which is considered overweight, was linked to having the lowest risk of death from all causes, the study authors said.

But both the Danish researchers and U.S. experts noted that longer life might not be better life, particularly if an obese or overweight person is struggling with chronic disease.

The startling finding stems from work led by Dr. Borge Nordestgaard, a clinical professor with the Institute of Clinical Medicine at the University of Copenhagen.

The analysis stacked BMI data against all-cause death statistics among three groups of Danes: 14,000 enrolled in a heart study during the mid-1970s; 9,500 enrolled in the same study in the early 1990s; and more than 97,000 who were enrolled in a lifestyle study between 2003 and 2013.

Today's weight classifications peg normal weight as having a BMI of between 18.5 and 24.9. Those with a BMI of between 25 and 29.9 are considered overweight, while anyone with a BMI of 30 or more is considered obese. BMI is a measurement based on height and weight.

The result in the Danish analysis: In addition to obesity-related early death risk dropping to normal-weight levels, the team found that the BMI level linked to the lowest rate of all-cause early death had gone up by more than three units, rising from 23.7 in the 1970s to 27 in 2013.

"On the BMI scale, a rise of 3.3 units is quite a lot," said Nordestgaard. "And a BMI of 27 is actually right in the middle of what we today call being 'overweight,'" he explained.

"But, of course, this is just one paper. Certainly the BMI categories for what is considered overweight and obese were defined by the World Health Organization based on data collected before the 1990s. So it might be that we should revisit what we now call overweight and obesity," Nordestgaard suggested.

"But we don't know what's cause and what's effect. And we only looked at the hardest endpoint, which is longevity, not quality of life. So even if you live longer today while being overweight, you might also be sicker. You might be alive, but with diabetes and cardiovascular disease, and problems with knees and joints -- things we didn't look at," Nordestgaard explained.

"And in the U.S., of course, obesity is often far in excess of a 27 BMI," he added. "So if you have a bad conscience about being a little bit overweight, that you're going to die early, maybe that's not actually the case. But our data should not be used as an excuse to eat a lot more or to become overweight if you are not."

That point was seconded by Lona Sandon, program director and assistant professor in the department of clinical nutrition at UT Southwestern Medical Center at Dallas.

"I do not believe it has necessarily become safer to have what is classified by U.S. National Institutes of Health as an overweight BMI," she said.

"A big difference between the decades is advances in drug treatment and other medical treatment that has helped people live longer, with or without overweight and obesity, and associated conditions," Sandon added.

But that does not mean being overweight has become healthier than in the past. It simply means that "doctors can just treat symptoms better," she cautioned.

"Whether you are optimal weight, overweight or obese, making an effort to reach your personal best for healthy eating and exercise is key for reducing risk of chronic disease," Sandon advised. "Regardless of size, healthy eating and exercise behaviors help protect our health and well-being."

The findings were published May 10 in the Journal of the American Medical Association.

More information

There's more on healthy weight advice at the U.S. National Heart, Lung, and Blood Institute.