University of Oxford researchers have just released the findings of a comparative study involving almost a million people. The research team used body mass index (BMI) as a means of measuring one’s health and it seems the more pounds one weighs, the shorter the life expectancy.

Body mass index is derived by mathematical formula – dividing weight in kilograms by height in meters squared. A BMI between 20 and 25 indicates a healthy weight. Between 25 and 29, one is overweight. Obesity occurs between 30 and 39 and morbid obesity begins at the 40 BMI mark.

The research team combined data from 57 studies that took place mostly in Europe and North America, involving almost one million people who were followed for 10 to 15 years. During the course of study, approximately 100,000 study participants died.

The study’s findings, published in a recent online issue of the British medical journal, ‘Lancet,’ include:

  • The lowest rate of death was in people with a BMI between 23 and 24.
  • The average life was shortened by about three years for people whose BMI was in the 30 to 35 range.
  • Life was cut short by 10 years when BMI rose higher than 40.

Losing ten years of one’s life due to morbid obesity is similar to the life expectancy of a life-long smoker, according to the study. Richard Peto says losing weight is a very healthy idea, especially when obesity is imminent. Peto, a professor at Oxford, is the main statistician in this comparative study.