Expert Commentary

The progressive increase of food waste in America and its environmental impact

2009 study from the National Institute of Diabetes and Digestive and Kidney Diseases published in PLoS ONE assessing the U.S. food supply, consumption and waste.

In 2008 rising food prices set off unrest around the globe, including in countries such as Argentina, Haiti, Cameroon, Egypt, Afghanistan and Indonesia. In late 2012 global indexes started to rise again after a long hot summer and extended droughts affected harvests in the United States, Europe and Russia. The production of biofuels also played a role, as every bushel of corn produced for fuel isn’t available for the dinner plate. These cross-cutting pressures have lead to renewed calls to further increase agricultural yields, even as humanity’s burden on global ecosystems continues to rise.

With the widespread increase in global food insecurity, the question of better utilizing the food we do produce has become increasingly important. Harvests have long been prey to pests and rot, but improved methods for storing and transporting food have not always resulted in decreased losses, as indicated by a 2009 study published in PLoS ONE. In “The Progressive Increase of Food Waste in America and Its Environmental Impact,” researchers from the National Institute of Diabetes and Digestive and Kidney Diseases — Kevin D. Hall, Juen Guo, Michael Dore and Carson C. Chow — analyze data from the United Nations’ Food and Agriculture Organization (FAO).

The authors note that since the 1970s the per capita U.S. food supply has progressively increased, and during the same period there has been a steady climb in obesity rates. They derived the amount of food waste in the United States by comparing food supply data with the calculated food consumed by the population.

The study’s findings include:

  • In 1974 approximately 900 kilocalories per person per day was wasted. In 2003 the amount of waste had increased more than 50%, to 1,400 kcal per person per day, the equivalent of 150 trillion kcal per year.
  • Solid food waste accounts for 30% of the total wasted food energy.
  • Food waste has increased from approximately 30% of the available food supply in 1974 to almost 40% in 2003.
  • The progressive increase of food waste suggests that the increase in U.S. obesity rates is the result of increased food availability, low prices and marketing.
  • Assuming that agriculture utilizes about 70% of the freshwater supply, 25% of total freshwater use is accounted for by wasted food.
  • On average, producing 1 kcal of food requires 3 kcal of fossil fuel energy; food waste thus accounts for approximately 300 million barrels of oil per year, about 4% of U.S. oil consumption in 2003.

The “progressive increase of food waste suggests that the U.S. 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 researchers write. They suggest that reducing the oversupply of food energy in the United States could help address the obesity epidemic as well as cut food waste and its environmental and energy-use consequences.

Related research: A 2013 study in the Proceedings of the National Academy of Sciences (PNAS), “Global Human Appropriation of Net Primary Production Doubled in the 20th Century,” looks at long-term trends in the pressure humanity exerts on the terrestrial biosphere. It found that from 1910 to 2005, the human population grew nearly fourfold — from 1.7 billion to 6.5 billion people — while economic output increased 17-fold. At the same time, human appropriation of net primary production doubled. While proportionally lower growth of HANPP is a positive, it still increased from 13% in 1910 to 25% in 2005, meaning that humans currently appropriate a full quarter of the net primary productivity of the biosphere.

Keywords: food, obesity, water, nutrition, fossil fuels

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