New research suggests Americans waste more food than they realize. People know about food waste, and say they care about the problem, but they underestimate their role in the accumulating waste.

According to recent survey conducted by researchers at John Hopkins University, some 75 percent of the 1,000-plus respondents claimed they wasted less than the national average. Somewhere between 30 and 40 percent of the U.S. food supply is thrown out -- most of it fruits and vegetables, and most of it tossed by households, restaurants and stores.

Participants in the study listed concerns about food safety and a desire to eat only the freshest produce as the top reasons why they throw out fruit and vegetables. The waste cost Americans more than $161 billion each year.

"Americans perceive themselves as wasting very little food, but in reality, we are wasting substantial quantities," study leader Roni Neff, director of the Food System Sustainability and Public Health Program at the Johns Hopkins Bloomberg School of Public Health, said in a press release.

"It happens throughout the food chain, including both a lot of waste by consumers, and a lot on our behalf, when businesses think we won't buy imperfect food. The root causes are complex," Neff added.

Though most of the Americans polled said they were concerned about food waste, only ten percent acknowledged the significance of environmental damage caused by wasted food. Each wasted piece of food requires extra fertilizers, pesticides and fossil fuels as part of the growth, harvesting, packaging and transportation processes.

"Consumer waste of food in the U.S. represents a powerful quintuple threat," Neff said. "Reducing it may improve food security, nutrition, budgets, environment and public health."

Researchers say their work, which was published this week in the journal PLOS ONE, offers an important educational opportunity.

"The survey results are especially relevant for three groups," Neff said. "For educators working to reduce food waste, a key finding is that highlighting financial savings may resonate more with consumers than other types of messaging. But there is still a need to explain the environmental effects of wasting food. For policymakers, our findings suggest a priority on making date labels clear and consistent, and encoding sell-by labels so they do not mislead consumers. And for businesses, the survey highlights changes consumers want, like offering re-sealable bags and smaller product sizes, and discounting damaged or near-expiration foods."