US food waste impacts climate, say scientists

By Caroline Scott-Thomas

- Last updated on GMT

Related tags Food waste Nutrition Food Obesity

US food waste impacts climate, say scientists
Americans waste about 1,400 calories-worth of food per person a day – or 40 percent of total food supply – with implications for climate change and obesity, claim US researchers.

The researchers, from the National Institute of Diabetes and Digestive and Kidney Diseases in Maryland, found that food waste has increased 50 percent since 1974, reaching about 150 trillion calories per year in 2003. This takes into account wastage right along the food supply chain, including waste from farms, manufacturers, retailers and consumers.

For the food industry, reducing waste could provide the dual benefits of lower costs and improved environmental sustainability – as consumers are increasingly taking ethical and environmental issues into account at the checkout.

The researchers, writing in the online journal Public Library of Science ONE​, claim that the impact of food waste on the environment has been largely – and surprisingly – overlooked in discussions of climate change mitigation.

“Food waste contributes to excess consumption of freshwater and fossil fuels which, along with methane and CO2 emissions from decomposing food, impacts global climate change,”​ they wrote.

The study estimates that food waste accounts for 25 percent of fresh water use in the United States, and 300 million barrels of oil – about four percent of the country’s total oil consumption.

Cheap food and obesity

In addition, the authors argue that the increase in food waste indicates an excessive quantity of cheap food, which could help to explain why the prevalence of obesity has increased so rapidly – from 15 percent in 1980 to 34.3 percent, with another 32.7 percent overweight, according to the US Department of Health and Human Services.

“The calculated progressive increase of food waste suggests that the US obesity epidemic has been the result of a ‘push effect’ of increased food availability and marketing with Americans being unable to match their food intake with the increased supply of cheap, readily available food,”​ the authors wrote. “Thus, addressing the oversupply of food energy in the US may help curb the obesity epidemic as well as decrease food waste, which has profound environmental consequences.”

The researchers also suggested that if America’s food waste problem were tackled, it could help ease global problems of food shortages and food price spikes.

They estimated the quantity of food waste by developing a mathematical model to calculate American food consumption based on body weight and metabolism, and comparing the results with information about the US food supply. On this basis, they claim that previous calculations may have underestimated American food wastage by up to 25 percent.

The full study can be accessed online here​.

Source: PLoS ONE

4(11): e7940. doi:10.1371/journal.pone.0007940 (2009)

“The Progressive Increase of Food Waste in America and Its Environmental Impact”

Authors: Hall KD, Guo J, Dore M, Chow CC

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