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The perfect figure for your BMI index

Work out your global fat scale!

It’s that time of year again when we see more of ourselves! August is the month for holidays and warm weather in the UK which means we wear less and may want to peel down to swimwear.

Suddenly our weight and size becomes more important and, along with the New Year, late summer is a key time for people to start diets after realizing they could look better and be healthier too.

Many of us just need to look in a mirror to know we are carrying a few excess pounds; but a good way to check the level of excess weight is the BMI index. Most of us will have heard of this now but will probably be surprised that it was actually devised in the mid 19th century, when between 1830 and 1850 a Belgian mathematician came up with an idea to measure fatness. He called it the Quetewlet Index of Obesity and his formula was to divide a person’s body mass or weight by the square of their height.

However, this idea wasn’t hailed as a major breakthrough and it wasn’t until the 1980s that BMI became an international standard for obesity measurement. Here in the UK it really became known in the late 1990s when the government launched new initiatives to combat the growing problem of people being overweight.

Other ratios have also been devised, including waist or hip measurements against height, but the BMI Index is now universally recognised.

However, knowing one’s BMI is not necessarily the end of it because unless the figure you come up with has some real meaning, it is just a number.

A number of authoritative bodies have come up with various thresholds to indicate BMI numbers and what this means in terms of being underweight, healthy or overweight.

Colourful tables are now produced which clearly illustrate where you are on the BMI Index. However, there is still debate on where the levels should be set for underweight, health and obese. But generally it seems that a BMI Index number of less than 18.5 is considered to be underweight;
18.5 to 25 is thought to be healthy; 25 to 30 is overweight and over 30 is obese.

Some authorities have broken this down further to the following:


< 18.50

Severe thinness

< 16.00

Moderate thinness

16.00 - 16.99

Mild thinness

17.00 - 18.49

Normal range

18.5 - 24.99


18.5 - 24.99


≥ 25.00


25.00 - 29.99

(≥ 30.00)

obese class I

30.00 - 34.99

obese class II

35.00 - 39.99

obese class II

≥ 40.00

But none of these figures are sacrosanct. Very fit people with high levels of muscle may come in with a higher BMI index yet still be very healthy.

But the BMI is an easy to use and useful tool that does seem to work. Two easy to use online calculators which include easy options for both metric and imperial measurements are on: NHS BMI calculator

The BBC has put together an interesting addition on all this by giving you an option to see where you are on a global fat scale!

They based this on research put together by a team from the London School of Hygiene and Tropical Medicine who, using UN data on population size in 177 countries, worked out an average BMI figure for each country and then globally.

In the BBC’s BMI online calculator, you can work out not only your BMI index but also where you are in comparison with the averages in countries around the world. I am not absolutely sure there is a lot of advantage in knowing my weight for my height is better than the average person in America, Australia or Thailand, but not as good as the average for Kenya or Japan; but it is interesting looking down the chart. Tonga leads the list with the fattest population, with America as expected high up there too. But surprisingly Greece and Turkey aren’t far behind them. The UK is better than Germany but not nearly as good as France.

More information on this is at:

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The above article is part of the features section of called laterlife interest. laterlife interest contains a variety of articles of interest for visitors to written by a number of experienced and new journalists.

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