About 40 per cent of food is wasted in the US, say scientists who found that most of the discarded food contains important nutrients that could have helped Americans meet their daily dietary needs.
Scientists at the Johns Hopkins University in the US calculated the nutritional value of food wasted at the retail and consumer levels, shining a light on just how much protein, fiber and other important nutrients end up in the landfill in a single year.
These lost nutrients are important for healthy diets, and some - including, dietary fiber, calcium, potassium and vitamin D - are currently consumed below recommended levels.
Nutrient-dense foods like fruits, vegetables, seafood and dairy products are wasted at disproportionately high rates.
Previous research estimated that as much as 40 per cent of food is wasted nationally, but it was not clear before this study how nutritious that food was.
"Huge quantities of nutritious foods end up in landfills instead of meeting Americans' dietary needs," said Marie Spiker, from Johns Hopkins.
"Our findings illustrate how food waste exists alongside inadequate intake of many nutrients," said Spiker.
For the study, the researchers calculated the nutritional value of the retail- and consumer-level food waste of 213 commodities in 2012.
The research team, looking at 27 nutrients in all, found that food wasted in the US food supply that year contained 1,217 calories, 33 grams of protein, 5.9 grams of dietary fibre, 1.7 microgrammes of vitamin D, 286 milligrammes calcium and 880 milligrammes potassium per person, per day.
Nutrient loss estimates provided by researchers could contribute to a baseline for measuring future progress, researchers said.
The study also highlights how the amount of nutrients lost to waste compares to nutritional deficits in the typical American diet.
For example, dietary fiber is important for maintaining digestive health and is found in grains, vegetables and fruits.
Researchers estimate that, in 2012, food wasted each day contained upwards of 1.8 billion grammes of dietary fiber, which is comparable to the full recommended intake for dietary fiber for 73.6 million adult women.
American women under-consumed dietary fibre by 8.9 grammes per day in 2012. The study found that the daily amount of wasted dietary fibre is equivalent to the amount needed to fill this nutritional gap for as many as 206.6 million adult women.
"While not all food that is wasted could or should be recovered, it reminds us that we are dumping a great deal of high quality, nutritious food that people could be enjoying," said Roni Neff, an assistant professor at John Hopkins.
The findings were published in the Journal of the Academy of Nutrition and Dietetics.