The world is getting fatter: the average adult is three times more likely to be obese today compared to 1975.

To illustrate the rapid rise of obesity rates around the world over the past 40 years, blogger Max Galka created this animated map for his Metrocosm site. The colour of each country represents its adult obesity rate in the year shown at the top left of the map.

World obesity map

The data for the map comes from research published earlier this year in The Lancet that looked at the body mass index of adults in 186 countries from 1975 to 2014.

The researchers found that worldwide obesity rates (defined as a BMI of 30 or more by the WHO) had increased from 3.2% in 1975 to 10.8% in 2014 for men, and from 6.4% to 14.9% for women.

During that period, the number of obese people worldwide rose from 105 million to 641 million.

Countries with the biggest obesity problem

While obesity rates are increasing around the world, some nations have experienced rocketing rates. China has overtaken the US as the country with the most obese people – almost 90 million and over 87 million, respectively. In 1975, only 0.5% of Chinese adults were obese. Today, that figure is around 8%.

The biggest changes occurred in some Pacific Island countries. In Samoa, Tonga and Tukalu obesity rates increased by more than 20%, double what they were in 1975.

Other countries topping the table include six English-speaking nations – the US, the UK, Australia, Canada, Ireland and New Zealand. They’re home to almost a fifth of the world’s obese population.

At the other end of the spectrum, North Korea’s and Japan’s obesity rates remained relatively low – with North Korea’s rising by about 1% and Japan’s by 2%.

Women are more likely to be obese

According to the study, there were 375 million obese women in the world in 2014, compared to 266 million obese men.

In Europe and the US, obesity rates for men and women are roughly equal. However, in southern African countries, women’s obesity rates are, on average, 20% higher than men’s.

 Age standardized obesity rates

If current patterns continue, the study estimates that by 2025 nearly one in five adults worldwide will be obese – around 18% of men and 21% of women. And 6% of men and 9% of women will be severely obese.

This could have enormous implications for global health. A high BMI can lead to noncommunicable diseases including cardiovascular diseases, diabetes, musculoskeletal disorders and some cancers, according to the WHO.

The WHO says the global obesity crisis is being caused by increased consumption of calorific and fatty foods, and a lack of exercise resulting from changing lifestyles, for example, the “sedentary nature of many forms of work, changing modes of transportation and increasing urbanization”.