"If you can get it into people's minds to talk about food waste, that's when little changes take effect," said lead author Kelly Whitehair, an instructor of hospitality management and dietetics at Kansas State University. "Change doesn't have to involve a huge elaborate campaign," she told Reuters Health.

Worldwide, up to half the food produced is wasted, according to an estimate published this week by the Institution of Mechanical Engineers, an independent London-based engineering society (see Reuters story of January 10, 2013 here: reut.rs/Vmb7Ca).

In the U.S., school cafeterias have been a particular target for change since students tend to waste a lot of food - especially those on all-you-can-eat meal plans typical at many colleges - but they may also be open to learning new habits.

To determine the best way to use written messages to change food waste behavior and get students thinking, Whitehair's team posted the simple slogans "All Taste... NO WASTE" and "EAT WHAT YOU TAKE, DON'T WASTE FOOD" for two weeks at campus all-you-can-eat dining halls.

The messages were placed near the cashier, food lines, tray drop-offs and as table place cards.

After two weeks, the researchers replaced the simple slogans around the cafeteria with new, more in-depth, data-laden messages that included statistics on food waste for an additional week.

Before, during and after the awareness campaign researchers collected and measured food scraps from 119,046 trays and weighed them.

On average, the school's 540 students wasted more than 57 grams (around two ounces) of edible food per tray - adding up to 1.5 tons of waste during the six-week study, the group reports in the Journal of the Academy of Nutrition and Dietetics.

About a third of the students wasted nothing over the whole study period, and a quarter of the students threw away less than 56 grams of food per meal. At the extreme, one student wasted over two pounds (998 grams) of food at a single meal.

Overall, food waste decreased from an average of 62 grams per tray in the beginning to 53 grams at the end of the study. Food waste levels did not decrease further, however, during the stage of the study that exposed students to more data-heavy messages, researchers found.

Nearly 40 percent of the students participated in accompanying surveys that showed little change in overall attitudes about food waste before and after being exposed to the simple slogans.

Whitehair and colleagues found that most wasted food came from self-serve items such as condiments and whole fruit.

The researchers weren't able to determine if students ate more or threw away less, since the amount on each tray at the beginning of the meal wasn't measured, to avoid alerting students to the fact that they were being studied.

However, one expert not involved in the study doubted that researchers measuring food on discarded trays would go unnoticed, and so questioned the study's findings.

Andrew Shakman, cofounder and president of LeanPath, a company that tracks foodservice-generated waste said the slogans and the presence of the researchers might have worked together to influence the results.

"There would have been an understanding that there was some degree of social surveillance going on," Shakman told Reuters Health. "Given that, the reduction isn't surprising."

Previous studies have shown that warning signs can reduce food waste, but Whitehair and colleagues concluded that simple slogans that cafeteria managers can produce with a computer and printer are just as effective as more complex marketing campaigns.

"The point was to look at ways to possibly reduce food waste that were really applicable to the (foodservice) managers - something that they could actually implement in their own operation without having to do some giant overhaul or remodel," Whitehair said.

Universities and colleges recognize that wasted food adds to expenses and have explored various strategies to keep food from ending in the trash.

The most common is tray-free cafeterias that "save us from our own eyes being too big for our stomachs and forces us to only take what we can carry," said Jonathan Bloom, author of American Wasteland and an independent food waste consultant. Bloom was not involved in the current study.

Dozens of universities have adopted tray-free dining halls and a recent independent study at American University in Washington, D.C., found that tray-free dining over a six-day period reduced waste by 32 percent.

Other strategies include single-day food weigh-ins to show students the amount they waste; offering samples before students order an entire entree; cooking stations that include make-your-own omelets, stir fry or grills so students can control ingredients and portions; and moving from all-you-can-eat to "à la carte" menus.

Tray-free dining typically yields 25-30 percent reductions in food waste according to a 2009 analysis of previous research. Experts said that many other strategies lack data to determine the effect on food waste levels.

The University of Newcastle in the U.K. is even exploring a "bin cam" - a camera that takes a picture of food waste from individual students, which then gets posted on social media sites.

Whitehair is satisfied with the evidence that even simple anti-waste slogans got students thinking, and the university has adopted the signs as permanent fixtures in its cafeterias.

During the research, Whitehair says, she overheard conversations as she scraped food from thousands of trays.

"It was funny, you'd hear these big guys go by and be like 'All taste, no waste today, baby.' Whitehair recalled.

"That's exactly why we did it, to get it in the kids' heads. That was enough for me," she said.

SOURCE: bit.ly/13bQqM6 Journal of the Academy of Nutrition and Dietetics, January 2013.

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