It’s an age-old public health question — how to preserve people’s ability to make their own choices while encouraging them to make good ones.

In the realm of food, it’s something that school administrators, health insurers and lawmakers have been thinking a lot about in recent years. Some approaches they’ve tried out are dramatic: for instance, banning sodas in school vending machines, or implementing a junk food tax. Others are more subtle. These so-called “nudges” often use positive cues and suggestions rather than rules to try to change behavior.

Here, five sneaky nudges that research has shown have the potential to make a real difference.

1. Think ahead

Getting kids to choose healthy meals has always been a challenge. But researchers at the University of Florida found a way to do it. They studied 70 students at a Florida school who used a software program to preorder their school lunches. Some placed their orders as usual, while others received behavioral “nudges” based on United States Department of Agriculture’s MyPlate recommendations. Kids who chose all five of the recommended food items got a screen with a smiley face. Those who did not, got a screen asking if they wanted to go back; while they could decline that offer, the “no” button was grayed out.

Researchers found that students getting the MyPlate nudges selected significantly more fruit, veggies, and low-fat milk than students in the control group. University of Florida researcher Gabrielle Miller believes that preordering takes away impulse selections. “It’s like that rule about making a list before you go grocery shopping,” she said. “You’ll make more healthful choices.”

2. Point the way

Speaking of groceries, researchers at New Mexico State University recently found that a good way to get people to buy, and subsequently eat, more fresh fruits and vegetables is to remind consumers where to find them.

In a 14-day pilot study examining the effects of in-store marketing, researchers selected two similar grocery stores in the same chain and with similar customer bases. The floor of one store got 6-by-3-foot arrows in highly visible areas, pointing toward the produce section. The arrows were marked with notes like, “Follow green arrow for health,” with images of fruits and vegetables and positive emoticons. The store with the arrows saw a significant increase in people’s spending on produce, but their overall spending didn’t go up — indicating that shoppers were trading prepackaged food for fresh food.

3. Buck the system

Teenagers often resist even the gentlest of directives to do anything, including healthful eating. So behavioral scientists tried harnessing that rebellion toward positive aims. And it seems to work.

Researchers divided up eighth-graders into groups. One got traditional healthy eating education; another group also got a discussion of healthy eating, but it was framed as a way to take a stand against the manipulative food industry. The next day, that group chose fewer junk food items from a snack menu than the other did. For the teens that got the “take a stand” message, there was a 7 percentage point increase in the rate at which they chose water over sugary drinks. They also also picked healthier snacks — like fruit, carrots or nuts — over chips or cookies at an 11 percent higher rate than they had prior.

“This treatment led eighth graders to see healthy eating as more autonomy-assertive and social justice-oriented behavior,” the researchers wrote. “Public health interventions for adolescents may be more effective when they harness the motivational power of that group’s existing strongly held values.”

4. Consider placement

Where food is located can make a big difference in whether it’s selected and eaten. Nutritionists, psychologists, and others are recommending that stores and restaurants put healthier options in favorable locations.

Food marketing researchers at Cornell University suggest that restaurants can design menus to emphasize healthier items by listing them first within sections and columns with bigger or more colorful typefaces. Cafeterias are also experimenting with moving salad bars closer to entrances and desserts farther away.

And we’re all used to the quick-grab goodies making up the obstacle course of temptation at the grocery checkout. University of Oxford scientists found that sales of healthy foods increased when they were placed closer to the cash register. The researchers noted that tricks like this worked even when people knew they were tricks. “Repositioning healthy foods is a simple, effective, and well-accepted nudge to increase healthy purchases,” wrote the researchers. “Moreover, disclosing its purpose does not impact on effectiveness.”

5. Win with words

Cornell researchers have found that restaurant menu items marked with descriptors such as “succulent” or “traditional” were ordered more often than items with plainer titles. They suggest using the technique with more healthful menu choices. For example, “tender grilled chicken,” instead of just “grilled chicken.” 

Catchy names work, too. In a study of 8- to 11-year-olds, carrots wereadded to their school lunches. When the carrots transformed into “X-ray vision carrots,” the kids crunched away 66 percent of them, but they ate only 32 percent of carrots with the the mild-mannered title “food of the day.” In another study, lunchtime vegetable sales went up 99 percent in a school that offered “Silly Dilly Green Beans” and “Power Punch Broccoli.”