We’ve often discussed on this blog the financial implications of an ageing population. Many (particularly western) nations are facing that reality at the moment and a greying world will become more prevalent in the decades to come. The financial implications are not just limited to the fact that there will be proportionately fewer members of society working in an older society, but also that the health of an older population is more expensive to take care of – as we age we tend to have more need of health resources. Now, today I do not want to talk about our ageing population (come back for that on Friday) but another demographic change that is placing financial strain on our health services: obesity. According to the British medical journal, The Lancet, new research shows that global obesity is now a bigger problem than global hunger.

Based upon pooled data from 1698 population-based studies totalling 19.2 million men and women aged 18 and over from 186 different countries, the study concludes that over the last 40 years the number of those in the world who are obese, as measured by the Body Mass Index (BMI), has increased by a factor of six! In 1975 105 million people were obese (a BMI of 30 and above), while in 2014 641 million people were obese. The world’s population also grew during that time of course, but as a percentage of the world’s population, the global proportion of those who are obese has grown by 167% over the last 40 years. Over that same timeframe, the global proportion of those that are underweight has decreased by 35%. Today, nearly 13% of the world’s population is overweight, and just over 9% is underweight. By 2025, if current trends continue nearly 20% of the world’s population will be obese. The health costs will continue to climb.

“Left unchecked, obesity will ‘bankrupt our already overwhelmed healthcare systems’, David Crawford, Alfred Deakin Professor and co-director of the Institute for Physical Activity and Nutrition at Melbourne’s Deakin University, said.”

However, this global average masks some fairly large differences between different countries. One-in-five obese people and one-in-six severely obese people live in the USA, Britain, Canada, Australia and New Zealand. (These countries comprise about 6% of the world’s total population.) The island nations in Micronesia and Polynesia have the highest average BMIs in the world, while the lowest are seen in East Timor, Ethiopia and Eritrea. However, the average BMI has grown in every geographical region of the world since 1975.

Although BMI has a measure of a healthy body weight is not totally accurate or perfect for individuals, according to Bruce Neal, professor of global medicine at the University of Sydney, for averages over large populations, it is a “pretty good measure”. And as long as the same measure is used across the years then it at least shows the trend and a valid comparison.

What a world we live in. As we’ve said before on this blog many times, it is clear that the world is getting older and that we are having fewer children. We’ve described the “grey tsunami” that is threatening to engulf many of our societies and economies. Perhaps we should say more accurately that it is a “grey, fat tsunami” that is facing the west. And it’s picking up speed as it gets closer to shore.

Marcus Roberts is a Senior Researcher at the Maxim Institute in Auckland, New Zealand, and was co-editor of the former MercatorNet blog, Demography is Destiny. Marcus has a background in the law, both...