Obesity a threat to food security

An urgent call to action on food re-localization

Detroit is apparently already a laboratory for this. I heard scholar and community activist Charles Simmons speaking last weekend about the situation in Detroit. He compared the situation in the inner city to Greece. Fresh food is by and large not available, most food is the unfood that's being sold in liquor stores. But they now have 1200 community gardens that will be feeding people this summer, and more are on the way.

http://www.biomedcentral.com/presscenter/pressreleases/20120618

The weight of nations: an estimation of adult human biomass

18 Jun 2012

The world population is over seven billion and all of these people need feeding. However, the energy requirement of a species depends not only on numbers but on its average mass. New research published in BioMed Central’s open access journal BMC Public Health has estimated the total mass of the human population, defined its distribution by region, and the proportion of this biomass due to the overweight and obesity.

Up to half of all food eaten is burned up in physical activity. Increasing mass means higher energy requirements, because it takes more energy to move a heavy body. Even at rest a bigger body burns more energy.

Using data from the United Nations and World Health Organization, researchers from the London School of Hygiene and Tropical Medicine estimated that the adult human population weights in at 287 million tonnes. 15 millions of which is due to the overweight and 3.5 million due to obesity.

While the average body mass globally was 62kg, North America, which has the highest body mass of any continent, with an average body mass of 80.7kg. North America has only 6% of the world’s population but 34% of the world’s biomass mass due to obesity. In contrast Asia has 61% of the world’s population but only 13% of the world’s biomass due to obesity.

If all countries had the same average BMI as the USA the total human biomass would increase by 58 million tonnes - this is the equivalent of an additional 935 million people of world average body mass.

Explaining the implications of this study Sarah Walpole said, “Our results emphasize the importance of looking at biomass rather than just population numbers when considering the ecological impact of a species, especially humans.”

This study was based on the 2005 WHO SURF report so it is an underestimate of the current situation. The world’s population is continuing to increase in size – the UN predicts that by 2050 there could be 8.9 billion people on the planet.

Prof Ian Roberts, continued, “Everyone accepts that population growth threatens global environmental sustainability – our study shows that population fatness is also a major threat. Unless we tackle both population and fatness - our chances are slim.”

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Notes to Editors

1. The weight of nations: an estimation of adult human biomass
Sarah C Walpole, David Prieto-Merino, Phil Edwards, John Cleland, Gretchen Stevens and Ian Roberts.
BMC Public Health (in press)

Please name the journal in any story you write. If you are writing for the web, please link to the article. All articles are available free of charge, according to BioMed Central’s open access policy.

Article citation and URL available on request on the day of publication.

2. BMC Public Health is an open access, peer-reviewed journal that considers articles on the epidemiology of disease and the understanding of all aspects of public health. The journal has a special focus on the social determinants of health, the environmental, behavioral, and occupational correlates of health and disease, and the impact of health policies, practices and interventions on the community.

3. BioMed Central (http://www.biomedcentral.com/) is an STM (Science, Technology and Medicine) publisher which has pioneered the open access publishing model. All peer-reviewed research articles published by BioMed Central are made immediately and freely accessible online, and are licensed to allow redistribution and reuse. BioMed Central is part of Springer Science+Business Media, a leading global publisher in the STM sector.

http://www.biomedcentral.com/1471-2458/12/439/abstract

Research article
The weight of nations: an estimation of adult human biomass

Sarah C Walpole, David Prieto-Merino, Phil Edwards, John Cleland, Gretchen Stevens and Ian Roberts


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BMC Public Health 2012, 12:439 doi:10.1186/1471-2458-12-439
Published: 18 June 2012

Abstract (provisional)

Background

The energy requirement of species at each trophic level in an ecological pyramid is a function of the number of organisms and their average mass. Regarding human populations, although considerable attention is given to estimating the number of people, much less is given to estimating average mass, despite evidence that average body mass is increasing. We estimate global human biomass, its distribution by region and the proportion of biomass due to overweight and obesity.

Methods

For each country we used data on body mass index (BMI) and height distribution to estimate average adult body mass. We calculated total biomass as the product of population size and average body mass. We estimated the percentage of the population that is overweight (BMI > 25) and obese (BMI > 30) and the biomass due to overweight and obesity.

Results

In 2005, global adult human biomass was approximately 287 million tonnes, of which 15 million tonnes were due to overweight (BMI > 25), a mass equivalent to that of 242 million people of average body mass (5% of global human biomass). Biomass due to obesity was 3.5 million tonnes, the mass equivalent of 56 million people of average body mass (1.2% of human biomass). North America has 6% of the world population but 34% of biomass due to obesity. Asia has 61% of the world population but 13% of biomass due to obesity. One tonne of human biomass corresponds to approximately 12 adults in North America and 17 adults in Asia. If all countries had the BMI distribution of the USA, the increase in human biomass of 58 million tonnes would be equivalent in mass to an extra 935 million people of average body mass, and have energy requirements equivalent to that of 473 million adults.

Conclusions

Increasing population fatness could have the same implications for world food energy demands as an extra half a billion people living on the earth. The complete article is available as a provisional PDF. The fully formatted PDF and HTML versions are in production.