A fifth of the world's food stock is lost to waste and over-eating, study shows
People over-eating consume 10 per cent more than they need while nearly nine per cent is thrown away or left to spoil.
This wasted food mountain could feed the one billion malnourished human beings around the globe.
Encouraging people to eat less meat and dairy, stop waste and not exceed nutritional needs could help to reverse these trends, say scientists.
Study leader Dr Peter Alexander, of Edinburgh University, said: "Reducing losses from the global food system would improve food security and help prevent environmental harm.
"Until now it was not known how over eating impacts on the system.
"Not only is it harmful to health – we found over-eating is bad for the environment and impairs food security."
He explained: "We need to look at what kinds of food we eat.
"Meat and animal products for instance are inefficient ways of producing calories because you need other foods to make them.
Meat and animal products for instance are inefficient ways of producing calories
Study leader Dr Peter Alexander
"We are not saying everyone should become vegan but thinking about our diet is a different way of looking at how we can all help in some small way – otherwise the world is going to get into serious difficulty."
Efforts to reduce these billions of tonnes could improve global food security – ensuring everyone has access to a safe, affordable, nutritious diet while preventing environmental damage.
The researchers analysed ten key stages in the global food system – including food consumption and the growing and harvesting of crops – to quantify the extent of losses.
People over-eating can consume 10 per cent more than they need
Using data collected primarily by the UN's Food and Agriculture Organisation they found more food is lost from the system than was previously feared.
Almost half of harvested crops – or 2.1 billion tonnes – are lost through over-consumption, consumer waste and inefficiencies in production processes.
Livestock production is the least efficient process with losses of 78 per cent – or 840 million tonnes.
Some 1.08 billion tonnes of harvested crops are used to produce 240 million tonnes of edible animal products including meat, milk and eggs.
This stage alone accounts for 40 per cent of all losses of harvested crops, said the researchers.
Increased demand for some foods – particularly meat and dairy products – would decrease the efficiency of the food system and could make it difficult to feed the world's expanding population in sustainable ways.
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Meeting this demand could cause environmental harm by increasing greenhouse gas emissions, depleting water supplies and causing loss of biodiversity.
In 2015 a UN report found if the amount of food wasted was reduced by only 25 per cent there would be enough to feed all the people who are malnourished.
Well-publicised attempts to combat the loss – such as laws in France that require supermarkets to distribute unsold food to charities – have highlighted the issue identified by the UN as one of the great challenges to achieving food security.
Dr Alexander's colleague Professor Dominic Moran, of York University, said: "This study highlights food security has production and consumption dimensions that need to be considered when designing sustainable food systems.
"It also highlights the definition of waste can mean different things to different people."
Estimates suggest by 2050 food production will need to have increased by 60 per cent on 2005 levels to feed a growing global population.
The wasted food could feed one billion malnourished people
In developing countries there are high levels of unintentional wastage – often due to poor equipment, transportation and infrastructure.
In wealthy countries there are high levels of 'food waste' which involves food being thrown away by consumers because they have purchased too much or by retailers who reject food because of exacting aesthetic standards.
The study published in the journal Agricultural Systems was funded through a Global Food Security Programme supported by the Biotechnology and Biological Sciences Research Council, Economic and Social Research Council, Natural Environment Research Council and the Scottish Government.
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