BETHESDA, Md.Food waste in the United States has increased by about 50 percent since 1974 to about 1,400 calories per person per day in 2003, reports a new study in Public Library of Science ONE (4(11): e7940. doi:10.1371/journal.pone.0007940 (2009)). All this adds up to 150 trillion calories wasted per American per year. In 1974, approximately 900 calories per person per day was wasted. Food waste has progressively increased from about 30 percent of the available food supply in 1974 to almost 40 percent in recent years.
The report also uncovers the environmental impact of the food waste. Its calculations imply that more than one-quarter of total freshwater use is accounted for by wasted food. Furthermore, given that the average farm requires 3 calories of fossil fuel energy to produce 1 calorie of food (before accounting for energy requirements of food processing and transportation), wasted food accounts for about 300 million barrels of oil per year representing about 4 percent of the total U.S. oil consumption in 2003. In addition, food waste rotting in landfills produces substantial quantities of methane a gas with 25 fold more potent global warming potential than CO2 , which would have been the primary end product had the food been eaten and metabolized by humans.
The researchers say the increase of food waste suggests 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. Thus, addressing the oversupply of food energy in the United States may help curb the obesity epidemic as well as decrease food waste, which has profound environmental consequences.