However, for more than twenty years now (since 1986) researchers have been monitoring the health a group of more than 22,000 doctors and, in one aspect of their research, have examined the relationship between weight and blood pressure in a sub-group of 13,563 male doctors whose blood pressure was normal at the start of the study.

Each year throughout the study period a wide variety of lifestyle data was collected and health measurements taken, including each participant's body mass index (BMI) and blood pressure, and these measurements have now been analyzed to produce a twenty year picture.

The BMI for men of a normal weight is 18.5 to 24.9 and the study used men with a BMI of 22.4 (the mean for normal weight men within this group) as their base for calculations. They then looked at the data collected to predict the likelihood of these men developing high blood pressure over the twenty years of the study.

Surprisingly, there was a marked increase even in those men who were only slightly above the mean figure of 22.4, but still within the normal weight range, with men between 22.4 and 23.6 being 20 percent more likely to develop high blood pressure. This risk then continued to rise as weight increased and it was found that obese men were 85 percent more likely than the lower end normal weight men to develop high blood pressure.

Most importantly, this figure of 85 percent was calculated on the basic not simply of BMI and blood pressure data, but also took into account such things as age, other health conditions (such as diabetes) and a wide range of lifestyle factors including smoking and exercise.

People suffering from obesity are well used to being told that this, that or the other is bad for them and carries risks but, more often than not, they tend to dismiss these on the grounds that the risk is probably not that high and that their chances of being affected are relatively low. In the case of high blood pressure though it would seem that the risk is high and the chances of being affected are far from low.