We know for a fact that obese people have a high risk for high blood pressure, diabetes and several types of cancer. According to a new study by British researchers at the University of Oxford, obesity can also shorten life. The study was published as a paper in the 18 March online issue of The Lancet.

 

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

 

For the study, Whitlock and colleagues from the Prospective Studies Collaboration collected data on 894,576 men and women who participated in 57 studies. The participants were mainly from Western and North America. Their average body mass index, BMI, was 25.

 

According to the US National Heart, Lung and Blood Institute, 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. BMI is a calculation that expresses a relationship between height and weight.

 

The researchers found that participants whose BMI was between 22.5 and 25 lived the longest. For a person 5 feet 7 inches tall, the optimum weight would be about 164 pounds, they noted.

 

But for participants with a BMI over 25, every 10 to 12 pound increase translated to about a 30 percent increased risk of dying. Moreover, 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 risk of dying was even higher in people who were moderately obese (BMI ranging between 30 and 35). They reduced their life span to two to four years, while those severely obese (BMI ranging between 40 and 45) reduced their life span by eight to 10 years. That is as life-shortening as smoking - but severe obesity is still rare, affecting about 2 percent of the population.

 

According to the latest statistics of the Centers for Disease Control and Prevention, obesity is continuously growing in the US, affecting more than one in four adults. While in 2005, 23.9 percent of US adults were obese or had a body mass index greater than 30, in 2007, the percentage had grown to 25.6 percent. This percentage translates in more than 60 million adults. Both poor diet and a lack of exercise are blamed.