Study estimates nutritional value of discarded food, highlighting need for programs and policies that prevent food waste
Researchers at the Johns Hopkins Bloomberg School of Public Health’s Center for a Livable Future calculated the nutritional value of food wasted in the U.S. 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 percent of food is wasted nationally, but it wasn’t clear before this study how nutritious that food was. While not all wasted food is consumable, a sizeable amount is, leaving researchers and policymakers looking for ways to minimize the amount of good food that gets tossed as millions of Americans go hungry, do not get enough nutrients or do not have access to healthy food options. The U.S. Department of Agriculture (USDA) and Environmental Protection Agency have set a goal of reducing food waste by 50 percent by 2030.
The findings will appear online May 15 in the Journal of the Academy of Nutrition and Dietetics.
“Huge quantities of nutritious foods end up in landfills instead of meeting Americans’ dietary needs,” says study lead author Marie Spiker, MSPH, RD, a CLF-Lerner Fellow at the Johns Hopkins Center for a Livable Future and a doctoral candidate in the Bloomberg School's Department of International Health. “Our findings illustrate how food waste exists alongside inadequate intake of many nutrients.”
For their study, the researchers calculated the nutritional value of the retail- and consumer-level food waste of 213 commodities in 2012, using data from the USDA’s Loss-Adjusted Food Availability data series. The research team, looking at 27 nutrients in all, found that food wasted in the U.S. food supply that year contained 1,217 calories, 33 grams of protein, 5.9 grams of dietary fiber, 1.7 micrograms of vitamin D, 286 milligrams calcium and 880 milligrams potassium per person, per day.
Nutrient loss estimates provided by this study could contribute to a baseline for measuring future progress, the authors say.
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 grams 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 fiber by 8.9 grams per day in 2012. The study found that the daily amount of wasted dietary fiber is equivalent to the amount needed to fill this nutritional gap for as many as 206.6 million adult women.
Many factors contribute to food waste at both the retail and consumer levels, including the disposal of food due to aesthetic standards, large portion sizes, and management of perishables in fridges and pantries. There is currently great energy around efforts to address waste of food. Preventing waste at the source is considered to be the optimal approach. Strengthening food recovery efforts that bring surplus food to food banks and pantries is also an important area of effort, innovation and impact.
“This study offers us new ways of appreciating the value of wasted food. 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,” says Roni Neff, PhD, an assistant professor in the Bloomberg School’s Department of Environmental Health and Engineering who oversaw the study and directs the CLF’s Food System Sustainability & Public Health Program. “We should keep in mind that while food recovery efforts are valuable, food recovery doesn’t get to the heart of either the food insecurity problem or the waste problem. We need strategies addressing these challenges at multiple levels.”
“Wasted Food, Wasted Nutrients: Nutrient loss from wasted food in the US and comparison to gaps in dietary intake” was written by Marie L. Spiker, Hazel A. B. Hiza, Sameer M. Siddiqi and Roni A. Neff.
This research was funded by the GRACE Communications Foundation. M. L. Spiker and S. M. Siddiqi were also supported by the CLF-Lerner Fellowship.