Overweight and obesity accounts for some four millions deaths around the world every year, a new study has found.

The prevalence of excess weight continues to increase worldwide and this is known to be a risk factor for a number of chronic diseases, such as heart disease, diabetes and some cancers.

Researchers set out to get a clearer global picture of the impact of excess weight on populations. They analysed data from over 68 million people in 195 countries in order to assess overweight and obesity trends in children and adults between 1980 and 2015.

The study found that in 2015, 10.7 million children and 603 million adults were obese. The overall prevalence of obesity was 5% among children and 12% among adults. Among adults, obesity was more common among women of all age groups.

Furthermore, since 1980, the prevalence of obesity has doubled in 73 countries ‘and has shown a continuous increase in most other countries'.

The study found that in 2015, high body mass index (BMI) contributed to four million deaths. Almost 40% of these deaths were in people who were overweight, rather than obese.

Body Mass Index is a means of assessing whether your weight may be posing a risk to your health, using your height and weight measurements. Those with a BMI of over 25 are considered to be overweight, while over 30 is considered obese.

The leading cause of death among those with a high BMI was heart disease, which accounted for 2.7 million deaths. Diabetes was the second leading cause of BMI-related deaths

The researchers said that ‘changes in the food environment and food systems' have a key role to play.

"Increased availability, accessibility, and affordability of energy-dense foods, along with intense marketing of such foods, could explain excess energy intake and weight gain among different populations.

"The reduced opportunities for physical activity that have followed urbanisation and other changes in the built environment have also been considered as potential drivers, however, these changes generally preceded the global increase in obesity and are less likely to be major contributors," they said.

The researchers noted that in recent years, a number of interventions have been suggested to reduce overweight and obesity, such as restricting the advertisement of unhealthy foods to children and using taxation to reduce consumption of unhealthy foods, such as so-called ‘sugar taxes' on fizzy drinks.

However, while some countries have started to introduce these measures in recent years, ‘no major population success has yet been shown'.

"Our results show that both the prevalence and disease burden of high BMI are increasing globally. These findings highlight the need for implementation of multicomponent interventions to reduce the prevalence and disease burden of high BMI," the researchers concluded.

Details of these findings are published in The New England Journal of Medicine.

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