The fat of the land: Estimating the ecological costs of overeating

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With every unfinished meal since Band Aid, you've heard it: "people are starving in Africa, y'know". True, the UN estimates that rich countries throw away nearly as much food as the entire net production of sub-Saharan Africa—about 230 million tonnes per year. But is it any less a waste to eat the excess food?

Morally, it's equivocal. Nutritionally, it depends. However: the land, water and carbon footprints are just the same.

In fact, researchers in Italy have proposed a way to measure the ecological impact of global food wastage due to excessive consumption. First, they estimated the net excess bodyweight of each country's population—based on BMI and height data—and distributed its among foods groups according to national availability.

Published in Frontiers in Nutrition, the results suggest that direct food waste—thrown away or lost from field to fork—is a mere hors-d'œuvre.

"Excess bodyweight corresponds to roughly 140 billion tonnes of food waste globally," reports group lead Prof. Mauro Serafini, of the University of Teramo. This figure is a snapshot of the current world population's accumulated dietary excesses, not a rate of overconsumption. It is, though, orders of magnitude higher than current annual direct food waste, estimated at 1.3 billion tonnes.

The disproportionate impact of Serafini's so-called 'metabolic food waste' grows when its ecological costs are calculated, using per-kilo values from thousands of food lifecycle assessments. Fruits, vegetables, roots and tubers have the highest direct wastage rates, but excess energy consumption is dominated by more calorie-dense foods. These typically entail more land, water and to produce.

So much so, that growing the world's metabolic food waste would be expected to generate the equivalent of 240 billion tonnes of CO2. This is roughly the amount mankind released burning fossil fuels over the last seven years combined. Notably the EU, North America and Oceania together contribute as much to this estimate as the rest of the world combined, with meat, eggs and dairy accounting for 75%.

The total land and water figures are more difficult to interpret, as they do not take into account how long land is required to grow different foods—or the redistribution of water, which is not lost per se via agriculture. And though based on public data collected by the UN, WHO, WWF and BCFN—an EU-backed nutrition think tank—the whole approach is fraught with methodological and conceptual uncertainty.

The calculations are based on national availability of the main food commodities, not average food intake or typical sources of excess calories among the overweight and obese. They assumed that bodyweight beyond BMI 21.7—midpoint of the 'healthy' range associated with lowest all-cause mortality—was all excessive, and all fat. How excess bodyweight is changing over time, or how much of it would vanish if were increased to healthier levels, are left unaddressed.

So, like Serafini we take metabolic with a pinch of salt. But as back-of-a-napkin estimates of the ecological costs of dietary excess, these figures are close to as good as we'll practically get. And they are monstrously high.

The glaring corollary: overeating is bad for our planet's health, not just our own. And as highlighted by this month's IPCC land-use report, overconsumption of farmed animal products by Westerners is probably the single biggest contributor.

Explore further

Less food wasted in South Africa than in Europe

More information: Elisabetta Toti et al, Metabolic Food Waste and Ecological Impact of Obesity in FAO World's Region, Frontiers in Nutrition (2019). DOI: 10.3389/fnut.2019.00126
Provided by Frontiers
Citation: The fat of the land: Estimating the ecological costs of overeating (2019, August 23) retrieved 23 September 2019 from
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Aug 23, 2019
A large reason why food is wasted today is because the segment of people who used to work in production and manufacturing have been replaced by automation and outsourcing/importing, and they now have to work in services to make a living - even though there's generally no need for such.

That means a disproportionate number of people are trying to make money by making other people consume more, and that includes food. The raw materials are cheap, so they try to sell by saturation: producing and pushing products in order to generate demand, rather than answering existing demand by production.

So the society gets overfilled with food. Everyone's trying to sell you a snack bar, a hamburger, or a meal in a restaurant. They make soda cups bigger than your thirst, fill your plate with twice as much food than you can eat, just to push more product and charge you money.

Of course people then eat too much.

Aug 24, 2019
"With every unfinished meal since Band Aid, you've heard it: "people are starving in Africa, y'know""

Band Aid? That was '84.
I was hearing that kind of line, when I was a kid, back in the late '50s.

Aug 24, 2019
Not to mention all the additional costs of transportation and to human health.

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