Underweight people at as high risk of dying as obese people, new study finds

March 28, 2014

Being underweight puts people at highest risk of dying, just as obesity does, new research has found.

The connection between being underweight and the higher risk of dying is true for both adults and fetuses. This is so even when factors such as smoking, alcohol use or are considered, or adults with a chronic or terminal illness are excluded, the study found.

The study, led by Dr. Joel Ray, a physician-researcher at St. Michael's Hospital and the hospital's Li Ka Shing Knowledge Institute, was published today in the Journal of Epidemiology and Public Health.

Dr. Ray's meta-analysis looked at 51 studies on the links between BMI and deaths from any cause, plus data on newborn weight and stillbirths in Ontario.

He found that adults who are underweight – with a BMI under 18.5 or less – have a 1.8 times higher risk of dying than those with a "normal" BMI of 18.5 to 24.9.

The risk of dying is 1.2 times higher for people who are obese (BMI of 30-34.9) and 1.3 times higher for those who are severely obese (a BMI of 35 or higher).

The researchers required that studies follow people for five years or longer, to weed out those who were underweight simply because of cancer or or heart failure. Common causes of being underweight include malnourishment, heavy alcohol or drug use, smoking, low-income status, mental health or poor self-care.

"BMI reflects not only , but also muscle mass. If we want to continue to use BMI in health care and initiatives, we must realize that a robust and healthy individual is someone who has a reasonable amount of body fat and also sufficient bone and muscle," Dr. Ray said. "If our focus is more on the ills of excess body fat, then we need to replace BMI with a proper measure, like waist circumference."

Dr. Ray also said that as society aims to curb the obesity epidemic, "we have obligation to ensure that we avoid creating an epidemic of adults and fetuses who are otherwise at the correct weight. We are, therefore, obliged to use the right measurement tool."

Explore further: Carrying extra weight could be healthier for older people

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2 comments

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Returners
not rated yet Mar 28, 2014
So much for the 7th day adventists vegan, near-starvation diet, not to mention several "more scientific" near-starvation diets that went around lately.

Sooo, anorexia and absurdly low calorie diets are more deadly that obesity.

Common sense really.

Fat exists to store energy for later, after all, which means it is obviously natural and situationally beneficial. Meanwhile, being severely under-weight has no obvious survival benefit.
Returners
not rated yet Mar 28, 2014
I even take issue with the upper limit of "normal" on that system.

Currently, I weight 210 and I'm 5'9" which means BMI 31

I can reasonably get back to 200 within several more months, since I've been losing at least some weight over time for the past year; cutting sodas and switching to lower sugar juices and punches has helped.

My height was the same my senior year in High School. I won a PFT ribbon in JROTC that year with at least a couple dozen points to spare, which probably less than 1/4 of the class each year qualified for the ribbon.

I know I weighed more than 168 pounds (the threshold for being "normal") even at that time.

A while back, I had planned on training at a gym with a former friend of mine, and he told me there was no way I could get down to those types of weights, that I probably could make like 190 at best.

He's one of those ~170 to 180 pound guys who can bench press more than twice his weight, and definitely not steroids...so he must know "real" fitness...

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