Obesity Takes Years Off Your Life

It's similar to smoking when it comes to effect on longevity, researchers note

Being obese can shorten your life, a new study shows.

"Moderate obesity typically shortens life span by about three years," said researcher Gary Whitlock, from the Clinical Trial Service Unit at the University of Oxford in the United Kingdom. "By moderate obesity, I mean weighing about a third more than is ideal, which for most people would mean being about 50 or 60 pounds overweight."

"By contrast, weighing twice your ideal weight -- say, an extra 150 pounds -- shortens life span by about 10 years," he added.

BMI is a calculation that expresses a relationship between height and weight (see my earlier post). People are considered underweight if their BMI is less than 18.5, normal weight when the BMI is between 18.5 and 24.9, overweight when BMI is between 25 and 29.9, and obese when BMI is 30 or more, according to the U.S. National Heart, Lung, and Blood Institute.

The researchers found that men and women whose BMI was between 22.5 and 25 lived the longest For those with a BMI over 25, every 10 to 12 pound increase translated to about a 30 percent increased risk of dying. In addition, there was a 40 percent increase in the risk for heart disease, stroke and other vascular disease, a 60 percent to 120 percent increased risk of diabetes, liver disease or kidney disease, a 10 percent increased risk of cancer, and a 20 percent increased risk for lung disease, the researchers reported.

"Obesity causes kidney disease, liver disease and several types of cancer, but the most common way it kills is by causing stroke and, most importantly, heart disease. Obesity causes heart disease by pushing up blood pressure, by interfering with blood cholesterol levels, and by bringing on diabetes," Whitlock said.

People who are moderately obese with a BMI in the 30 to 35 range reduced their life span by two and four years. For those who are severely obese with BMIs between 40 and 45, their life span was reduced by eight to 10 years. That's comparable to the effects of smoking, Whitlock said.

In fact, people whose weight was below normal also died earlier, due mainly to smoking-related diseases, the researchers noted.