London, Mar 18 While it is said that being severely overweight reduces life expectancy, a new study has found that even mild obesity can take years off one's life.

The study has found that if a person is moderately overweight, he/she will probably live two to four years less than if they stick to their ideal weight.

A research team, led by Richard Peto and Gary Whitlock of the Clinical Trial Service Unit at the University of Oxford, pulled together data from 57 studies.

They looked at almost 900,000 people, mostly from Europe and North America, to see whether those with a higher body mass index (BMI) were more likely to die early.

BMI is a measure of how obese a person is, based on their weight and height (calculate yours here). The ideal range is 22.5 to 25 kilograms per square metre.

The researchers found that people whose BMI was higher than 25 kg/m2 had shorter lifespans on average.

They also found that those who were moderately overweight, with a BMI between 30 and 35 kg/m2, lived two to four years less.

People who were severely obese, with a BMI between 40 and 45 kg/m2, lived eight to ten years less on average - a reduction comparable to that caused by smoking.

"Excess weight shortens human lifespan. If you are becoming overweight or obese, avoiding further weight gain could well add years to your life," New Scientist quoted Whitlock, as saying.

The study is published in The Lancet. (ANI)