Many calculations about global resources rely on the current
and projected world population. However, we may be off by quite a bit by not
taking obesity into account. According to Sarah Walpole and her colleagues from
the London School of Hygiene and Tropical Medicine, we should be measuring
total human biomass rather than counting individuals.
Biomass is the total mass of
whatever biological entity you’re interested in. It could be every living thing
on Earth, or all plants, or all red pandas. The human biomass is the combined
mass of all humans on Earth.
Clearly, fat people have more mass
than skinny people. Heavier people not only take up more space than thin people
(which is rarely an issue), but they use up more resources, which can be
significant when we’re counting up how much of something there is to go around.
It simply takes more energy to sustain a larger body than a smaller one. Thus,
if you have a population of obese people, they’re going to use up resources
much faster than the same number of thin people would have.
The researchers used information
from the United Nations, the World Health Organization and national databases
to estimate the population and the mean body mass index (BMI) of adults in 190
countries. From this, they extrapolated to the total adult human biomass of the
planet.
The scientists estimated that in
2005, the total adult human biomass of the planet was about 287 million metric tonnes.
If none of those people had been overweight, the total would have been about 15
million tonnes less, or about a 5% difference.
The researchers then compared two
different scenarios. In the first, the entire planet had BMIs in the same
distribution as that seen in Japan, and in the second, the whole world looked
like the U.S. These represented normal weight and fat extremes, as it takes
about seventeen Asians to make up the same body mass as twelve Americans. If
the whole world looked like Japan, it would be the equivalent of losing almost
a quarter of a billion people from the world population. On the other hand, if
every place looked like the U.S., it would be like gaining close to a billion
new inhabitants.
There were some limitations to
this study, not least of which was that they did not include children, who make
up quite a large fraction of the human biomass, obese or otherwise. And of
course, these are only rough estimates. However, it’s important to note that
projections about how many people an area can feed or how long a resource is
expected to last may be vastly underestimated if people use population counts
without adjusting for biomass. As there’s every indication that the rest of the
world is emulating the U.S. and not Japan, the discrepancy between predicted
resource usage based on population and actual usage will only get greater.
I think we could well see some improvement if we started to follow the simple dietary advice of that medical sage Billy Connolly:
ReplyDelete"Don't eat anything that comes in a "bucket"! Buckets are the kitchen utensils of the farm yard!"
Sound advice I'm sure you'd agreee :)
You're very welcome.
ReplyDelete