BMI: A big issue

Published on 05/08/2012 00:00

Body Mass Index (BMI) is commonly used by doctors to determine if an individual is overweight or obese. It is defined as a patient’s weight in kilograms divided by the square of his or her height in metres.

Patients with a BMI of 30 or more are categorised as one of three classes of obesity – the third and most serious being morbid obesity. Caused in most cases by an imbalance between energy input and expenditure, obesity is linked to a range of health problems, including Type 2 diabetes, cardiovascular disease and some cancers.

For those with a BMI of 25 – overweight – there is an “increased risk” of developing further health-threatening conditions. This rises to “medium to high” at 30 and “very high” at 40.

Those with BMI of 40-50, are referred to as super obese.Median survival for those classed as morbidly obese is reduced by as much as eight to ten years, compared with adults of normal weight.