As much as half of our food goes to waste even as nearly a billion people remain underfed in poorer countries. What measures and technologies could help us get on top of the problem?
How much perfectly edible food do you chuck away? If about half ends up in the bin, it would echo the results of a study published today. It estimates that of the 4 billion metric tons of food we produce each year, between 1.2 and 2 billion tons never gets eaten.
That's not an edifying statistic, given that according to the UN Food and Agriculture Organization, 870 million people remain underfed in poorer countries. What are the resource implications of this waste, and what measures and technologies could we adopt, now or in the near future, to get on top of the problem?
The reasons food is wasted differ between rich, poor and intermediate countries, but waste is most profligate and avoidable in rich countries, says the Institution of Mechanical Engineers in London, in a report entitled Global Food: Waste not, want not.
Typically, around half of food in richer countries is binned. In the US, big contributors to waste include supersized portions that customers simply can't manage, and "eat as much as you want" offers in restaurants. In the UK, over-conservative sell-by dates on labels and two-for-one offers of perishable items are key factors, encouraging consumers to buy too much food to start with and to throw away items that have reached their sell-by date, but which are still edible.
The problem, says the report, is that the sell-by dates are selected not to protect us from rotten food, but to give supermarkets huge safety margins ? minimising any risk of consumers eating their products, getting ill and then suing them.
No ugly veg please
Another factor in rich countries is that consumers may shun oddly shaped vegetables. This, says the survey, leads to as much as 30 per cent of vegetable harvests being rejected by supermarkets ? again, a huge and unnecessary waste.
In developing countries, poor transport and storage systems lead to much food being lost before it even gets to the shop: for example, 45 per cent of rice is lost in this way in China, and as much as 80 per cent in Vietnam. In the poorest countries, much food is also lost through poor handling by farmers.
All this is bad enough, but it gets even worse when the resources used to produce wasted food are taken into account. Huge amounts of water go to waste with every morsel thrown in the bin. The report says that about 70 per cent of our fresh water globally goes into producing food, with meat being far more resource-hungry than vegetables. Each kilogram of beef requires 15,415 litres of water, compared with 237 litres for a kilo of cabbage. Chocolate is even more water-hungry, though, needing 17,196 litres per kilo.
Energy input
Then there is the energy squandered in producing wasted food. Typically, says the report, 7 to 10 calories go into producing every calorie we get from food. Again, meat is the most costly, with beef requiring 35 calories per calorie of nutrition, compared to 3 calories for veg. In richer countries, much of the energy on the production side goes into making fertiliser and pesticides, which account for half the energy needed to grow wheat, for example.
One day, it may be possible for all crops to make their own fertiliser directly from nitrogen in the air, just as peas and beans do at present, but it will take decades for this research to yield results. Meanwhile, the energy wasted each year in discarded food in the US exceeds that obtained from the country's offshore oil and gas reserves.
Wasting food also has implications for land use. Around half the world's 100 million square kilometres of fertile land is already used to grow food. A single hectare can supply rice or potatoes for 19 to 22 people, but would only feed one or two if turned over to producing lamb or beef, says the report.
That use of precious land is in vain if food is thrown out. It may be that all meat will one day be "grown" as tissue in large fermenters, which would reduce the area required to produce beef, for example, by 99 per cent, while also saving huge amounts of water. But again, that day is decades away.
Cutting out waste
The best, fastest and simplest solution to all this waste, says the report, is for consumers in rich countries to buy less food and make better use of what they do buy, throwing less away. Developing and poorer countries should work towards better transport links and adopt technologies that raise yields and prevent waste in harvesting and storage.
"The potential to provide 60 to 100 per cent more food by simply eliminating losses, while simultaneously freeing up land, energy and water resources for other use, is an opportunity that should not be ignored," concludes the report.
If we simply can't break our habit of chucking food out, there is an emerging, if slightly yucky, idea that could help us out ? using maggots to convert food waste and even manure into protein that can be fed back to animals.
But for now, while all these potentially game-changing technologies develop, the best solution has to be to buy less and make sure you eat it.
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