US increasing food waste
Food waste contributes to excess consumption of freshwater and fossil fuels which, along with methane and CO2 emissions from decomposing food, thus impact global climate change. In a recent paper published in the Public Library of Science ONE, researchers at the National Institute of Diabetes and Digestive and Kidney Diseases calculate the energy content of nationwide food waste from the difference between the US food supply and the food eaten by the population. The latter was estimated using a validated mathematical model of human metabolism relating body weight to the amount of food eaten. The researchers found that US per capita food waste has increased by about 50% since 1974 reaching more than 1400 kcal per person per day in 2003, i.e. 150 trillion kcal per year. Food waste has risen from almost 30% of available food in 1974 to 40% today. Previous calculations are thought to have underestimated food waste by as much as 25% in recent years. Obesity in the USA has risen from 15% of the population in 1980 to 34.3% according to the US Department of Health and Human Services. This increase of food waste suggests that "the US obesity epidemic may have 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 suggest that addressing the oversupply of food energy in the USA could help curb to the obesity epidemic as well as reduce food waste, which would have profound consequences for the environment and natural resources. For example, food waste is now estimated to account for more than one quarter of the total freshwater consumption and more than 300 million barrels of oil per year, representing about 4% of the total US oil consumption.