This not only concerns the UK Government, who have just announced a concerted campaign to tackle the problem via GP's, but also the life insurance industry.

The problem is that many people are still sensitive about their weight. Sensitive to the extent that they'll convince themselves that they're sticking to a diet when they are patently not. The loss of a pound or two occasions celebration, whereas the same two pounds going back the next day remains unannounced. Ring any bells for you?

Well normally, a porky or two about your true weight doesn't harm anyone - other than perhaps yourself. But now life insurance companies are having to take a much closer interest. They suspect that lots of people are telling lies about their weight on their life insurance applications.

Consequently, Scottish Provident, one of Britain's biggest life insurers, is tightening up its application procedures. Now, as well as asking applicants how much they weigh, they'll be asking when they last weighed themselves. It's an attempt to encourage applicants to answer more accurately rather than pluck a figure out of thin air or being economical with the truth.

A spokesman for the insurer said, "We know that people normally understate their weight, mainly because they are in denial about the subject, although there are also some people who will lie just to get cheaper premiums".

The British Medical Association classifies someone as "obsess" if their Body Mass Index (BMI) exceeds 24 but most insurance companies are now using 30 as their obesity definition. Above that figure and you'll find that they'll load your premium and even ask to have a medical examination. Anyone who is overweight could easily see their life or critical illness insurance premium loaded by up to 50% - and extreme cases, cover will be refused.

So, if you want to know your BMI, take your height in meters and multiply it by itself. Then take the result and divide it by your weight in kilograms. The result is your Body Mass Index.

Whilst BMI has become the accepted method of assessing someone's weight, it does have limitations as it doesn't discriminate whether the weight is being carried in fat or muscle. And a study of 33,000 adults reported recently in The Lancet, concluded that the medical profession's "over 24" BMI obesity definition could be raised to "over 25" without harming health. That's the equivalent of adding an extra half stone. Their research also found that only adults with BMI's in excess of 35 suffered a pronounced lowering in life expectancy.

But in accepting a BMI level of 30, the life insurance industry has taken a cautious mid position. Well, if it was your money at risk, wouldn't you?