National Obesity Awareness Week – is it all about BMI?

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It’s National Obesity Awareness Week in the UK and on Monday we re-posted a blog by Nutritional Therapist Rosie Letts discussing some reasons it might be difficult to lose weight.

Today, we wanted to provide some information about how obesity statistics are calculated and show that it might not be the best measure for understanding each of us as individuals.

Firstly, the statistics:

  • Adult obesity in England has risen from 15% of adults in 1993 to 26% in 2016.
  • One in five children in Year Six and one in 10 children in Reception were classified as obese in 2016.
  • In 2017, the UK was named the most overweight nation in Western Europe
  • Obesity is related to higher risk of chronic illnesses, particularly hypertension, cholesterol, diabetes and cardiovascular diseases.
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Health Survey for England 2016

But it’s not only about BMI…

Whilst these statistics are worrying and are often used to try and frighten people into losing weight, they are also based on a single measure, known as BMI (Body Mass Index).

BMI is measured by dividing your weight (in kg) by your height squared (in cms). Whilst it is useful for comparison purposes over time and across populations, this measure has been criticised as not taking into account other factors, such as gender, muscle mass and distribution of fat around the body, and for showing skewed results for children and the elderly.

This can lead to people being classified as overweight or even obese despite them being fit and healthy and appearing in proportion.

As a result, health practitioners now use other measures to provide a more comprehensive picture of an individual (although these are not yet used in population statistics). These measures include waist-to-hip ratio, which is measured by dividing your waist circumference by your hip circumference and should be 0.9 or less for men and 0.85 or less for women.

And a more recent addition to this list is Relative Fat Mass and is based on the following formula:

For men: 64 – (20 x height/waist circumference) = RFM

For women: 76 – (20 x height/waist circumference) = RFM

A combination of the above measures is likely to give the best picture for each of us as individuals.

One final point. When people are overweight, it may be a result of them eating too much food and not exercising enough, but this simplifies the issue and does not take into account the individual and their lifestyle, stress levels, sleep, erratic working hours, mental health, genetics, physical injury or a myriad of other issues.

We are all individuals and, whilst we need to understand that being obese brings additional health risks, we also need to focus on our own personal body, health and circumstances and the key elements of a healthy diet, adequate hydration, regular exercise, stress management and spending time outdoors.

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