Why Waist to Height Ratio Better Than BMI

What is BMI-?

The body mass index measurement, put simply, is the calculation of someone’s body weight in relation to their height. Using a chart or a calculator, you enter your weight and height details and are then told your current BMI measurement. You can also use this method to discover what your ideal weight should be for your height, a useful tool in today’s climate of thin celebrities and fad diets.

In broad terms, a BMI of fewer than 18.5 places you in the underweight category and between 18.5 to 24.9 you are deemed normal - this is what we should all be aiming for. This move on to being overweight with a BMI of between 25 to 29.9, obese at over 30 and morbidly obese if you have a BMI of over 40.

To put the BMI calculations into practice, the normal weight range for a US male of average height of around 1.76m is between 130lbs and 165lbs. For a US woman with an average height of just over 1.62m, the BMI measurement for a normal weight is between 105lbs and 140lbs.

Check your body mass index calculation with our BMI calculator.

If you are unable to use our BMI Calculator, or if you are interested in how BMI is calculated, this page has the mathematical BMI Formula.

BMI Classification

18.5 Or less Underweight

18.5 to 24.99 Normal

25 to 29.99 Overweight

30 to 34.99 Obesity (Class 1)

35 to 39.99 Obesity (Class 2)  

40 or greater Morbid Obesity

 

English BMI Formula

BMI = (Weight in Pounds / (Height in inches x Height in inches)) x 703

Metric BMI Formula

BMI = (Weight in Kilograms / (Height in Meters x Height in Meters))

Many do argue that the results BMI measurements provide are too general and do not consider the gender, build, age or ethnicity of a person. For example, professional athletes are often considered overweight or obese when using BMI measurements due to their muscle content, which weighs more than fat. Similarly, as people age their bone density decreases, so although they may seem to have a weight within the normal BMI range, their measurement actually needs to be scaled-down to reflect this.

With rising levels of obesity and obesity-related illnesses, throughout the developed world, it’s fair to say anything that educates people about their weight is a good thing. BMI measurements may be a contentious issue, but with the health benefits of having a normal BMI reading being a reduced risk of diabetes, high blood pressure, heart disease, stress on your joints and overall, early death, it shouldn’t be ignored and could play a important role in helping you to manage your long-term health.

New Research -Waist to Height Ratio Better Than BMI

Waist to height ratio is a better predictor of heart disease and diabetes risk than BMI, according to new research presented at a scientific meeting recently.

Study leader Dr Margaret Ashwell, an independent consultant and former science director of the British Nutrition Foundation, presented the findings at the 19th Congress on Obesity in Lyon, France, on Saturday 12 May. Keeping your waist circumference to less than half your height can help increase life expectancy for every person in the world, said Ashwell, as reported in the Telegraph.

Man who is 6ft or 72 inches tall (183 cm), should keep his waist under 36 inches (91 cm)

Woman who is 5ft 4 in or 64 inches tall (163 cm), should keep her waist measurement under 32 inches (81 cm).

Ashwell said the measure should be considered as a screening tool. The idea of using Waist to Height Ratio (WHtR) to predict cardiometabolic risk is not new, but is coming to prominence as more studies reveal its value.At the meeting, Ashwell presented the findings of a study that analyzed the health of 300,000 people and found WHtR was better able to predict high blood pressure, diabetes, heart attacks and strokes than BMI.BMI (short for Body Mass Index) is a widely used measure of obesity. It is a ratio of a person's weight in kilos to the square of their height in metres. However, it does not take into account the distribution of fat around the body.

Abdominal fat affects organs like the heart, liver and kidneys more adversely than fat around the hips and bottom, in terms of cardiometabolic risk. Last year, Ashwell co-authored a paper on the increasing importance of using Waist-to-Height Ratio (WHtR) to assess cardiometabolic risk, and pleaded for scientists to use a consistent terminology to express the ratio so it can easily be searched for in the literature.

An advantage of WHtR is the simplicity of the health message "keep your waist circumference to less than half your height". This is a much easier thought to hold in mind than BMI, where not only do you have to work out the ratio of your weight in kilos to the square of your height in metres, but also remember what the healthy range is. To measure the waist circumference accurately, you should measure it mid-way between the lower rib and the iliac crest (the top of the pelvic bone at the hip), this is the method recommended by the World Health Organization, says Ashwell.

(Source-19th Congress on Obesity in Lyon)