The amount of land used annually to grow food that ends up in the garbage in the United States is 30 million acres, or seven percent of total US cropland. Some 4.2 trillion gallons of irrigation water gets wasted, too, said the report in the journal PLOS ONE.

Fruits and vegetables made up 39 percent of total food waste, followed by dairy (17 percent), meat (14 percent) and grains (12 percent).

Items least likely to be thrown out included salty snacks, table oils, egg dishes, candy and soft drinks.

“Higher quality diets have greater amounts of fruits and vegetables, which are being wasted in greater quantities than other food,” said co-author Meredith Niles, an assistant professor at the University of Vermont.

“Eating healthy is important, and brings many benefits, but as we pursue these diets, we must think much more consciously about food waste.”

The report, based on government data and surveys about food waste from 2007 to 2014, found that the amount of wasted food equals about 30 percent of the average daily calories consumed for every American.

The costs to the environment and to farmers are “significant,” it said.

“Food waste corresponded to harvests produced with the use of 780 million pounds of pesticide and 1.8 billion pounds of nitrogen fertilizer, annually.”

Solutions may include teaching consumers how to better prepare and store fresh fruits and vegetables, revising “sell-by” dates, encouraging people to buy imperfect produce, and incorporating efforts to prevent food waste into government sustainability programs.

“Food waste is an issue that plays out at many different levels,” said lead author Zach Conrad at the US Department of Agriculture’s Agricultural Research Service in North Dakota.

“Looking at them holistically will become increasingly important to finding sustainable ways of meeting the needs of a growing world population.” DM