The research, published in the Bulletin of the World Health Organization today, analysed increases in the food energy supply and obesity in 69 countries (24 high-, 27 middle- and 18 low-income) – finding that both body weight and food energy supply had increased in 56 (81%) of them between 1971 and 2010.
What’s more, in 45 (65%) countries the increase in available calories was enough or more than enough to explain the concurrent increase in body weight, said the team – led by Stefanie Vandevijvere from the University of Auckland, New Zealand.
"We know that other factors have also changed over these decades such as increased urbanization, car dependence and sedentary occupations, which are also contributing to the global obesity epidemic," said Vandevijvere.
"However, our study shows that oversupply of available calories is a likely driver of overconsumption of those calories and can readily explain the weight gain seen in most countries," she said.
Vandevijvere added that much of the increase in available calories over the decades has come from ‘ultra-processed food products’, “which are highly palatable, relatively inexpensive and widely advertised, making overconsumption of calories very easy.”
The team warned that their findings are important because they provide further evidence that governments need to implement policies to make the food supply healthier and, in turn, reduce obesity, which is a risk factor for many health problems, including diabetes, heart disease, stroke and some cancers.
Vandevijvere and her colleagues compared data on food energy supply and average adult body weight in the 69 countries from the United Nations Food and Agriculture Organization (FAO) database and several databases on average adult weight, including the World Health Organization (WHO) global database on body mass index (BMI), between 1971 and 2010.
The FAO estimates the food supply of countries by balancing local production, country-wide stocks and imports with their exports, agricultural use for livestock, seed and some components of waste. Waste on the farm and during distribution and processing are usually taken into account but not losses of edible food, such as domestic animal feed, plate-waste and other food that is thrown away.
The team found that between 1980 and 2013, the proportion of adults globally who were overweight increased from 28.8% to 36.9% in men, and from 29.8% to 38% in women.
Average increases in food energy supply varied by country and some of these levels were strikingly high, they said. For example in Canada food energy supply increased by 559 calories per person per day between 1971 and 2008, while in the USA and Fiji, it was 768 and 550 calories over a similar time period.
These increases are far in excess of the amount required to explain the weight gain experienced by each country - suggesting that food waste had also increased substantially, said the team.
"Countries need to look at how they guide the food system,” said Dr Francesco Branca, director of the Department of Nutrition for Health and Development at WHO. “This means working across several sectors including agriculture, the food production, distribution and retail industries, health, social welfare and education,"
According to the team, a combination of policies is needed, including restriction of the marketing of unhealthy foods to children, front-of-pack supplementary nutrition labelling, food pricing strategies, and improving the nutritional quality of foods in schools and other public sector settings.
"We also need to consider how trade and investment agreements and agricultural policies affect domestic food environments, people's diets, and the disease patterns in countries," said Vandevijvere.
Source: Bulletin of the World Health Organization
Volume 93, Pages,446-456, doi: 10.2471/BLT.14.150565
“Increased food energy supply as a major driver of the obesity epidemic: a global analysis”
Authors:Stefanie Vandevijvere, et al