Is there a global obesity epidemic?

We all know that many western countries have a growing health problem due to our expanding waistlines. When did this obesity epidemic start? Is it the same in all countries and why didn’t we see this happening?

To investigate the global obesity epidemic I have used the Body Mass Index (BMI).The BMI is simply your body weight (kg) divided by your height squared (m2). The BMI value is routinely used to categorise if a person is:

1. Underwieight (BMI<18.5kg/m2)
2. Normal Weight (18.5kg/m2<BMI<25kg/m2)
3. Overweight (25kg/m2<BMI<30kg/m2)
4. Obese (BMI>30 kg/m2)

Clearly the world is getting fatter (Figure 1) – but the pattern is uneven. The blue countries (most of Africa and Asia) are in the underweight to normal range (BMI<25), and the red countries are in the overweight to obese range (BMI>25). The grey countries are those with weight close to 25 kg/m2 (the upper end of the normal range). Figure 1 covers the period 1980-2008, so it gives a nearly 30 year series to track the trend in BMI by country.

Figure 1: Annual Body Mass Index by country – click on a country to see the underlying data (source: Gap Minder).

Some observations about BMI change through time

The United States was a clear early leader in the obesity stakes followed by Canada, Australia, Argentina and several European countries. Kuwait and Saudi Arabia lead the middle east in weight gain.

Russia is leading a late charge and making up for lost ground with a very rapid rate of BMI increase since 2000.

Many South American countries have transitioned from blue to red over the data period (E.g. Brazil, Ecuadore, Paraguay, Chile).

The Democratic Republic of Congo is the only country with a lower BMI in 2008 than in 1980. The neighboring Central African Republic had a decline in the late 1990’s but has since recovered. These two countries have experienced very severe civil unrest and famine. I suspect that their lower BMI scores have nothing to do with any government ‘healthy choices’ media campaign.

The most obese countries

While many countries (mostly Africa and Asia) are still in the normal weight range, the rise in BMI is definitely a global phenomenon. In 1980 there were 41 countries with a BMI aver 25 (Overweight) and none in the obese range. Twenty-eight years later (2008) there were 116 countries with average BMI values above 25 (and seven countries in the obese range).

Nauru tops the BMI league table with a series other pacific nations close behind. The Unites States comes in at number 10. The Czech Republic is the highest ranked country in Europe(17th) however there is a long string of almost identical BMI values across most o fthe developed world.

Figure 2: Top 25 countries by Body Mass Index – showing their comparative 1980 BMI values

The data

The BMI data here comes from GapMinder – A tremendous collection of aggregated health and well being data – who in turn cite the source of the BMI data as the Royal College of London. To keep the story simple I have averaged the male and female BMI values to give a country average (the average male BMI is about 1-1.5 kg/m2 greater than the female BMI score). The data is suspiciously complete, and suspiciously linear (see Australia). I suspect the underlying data has been infilled to form a completed record. None the less, the trends are clear.

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