Students eat junk. Can science help?

By | October 5, 2019

For 10 weeks, five days a week, four hours a day, three years ago, Matheus Mistura, a decorated grad student with a glittering academic career, stood next to a hot table in a cramped cafeteria peeping at students’ plates. On cold days and on hot, on rainy days and clear days and days when he’d rather be doing anything, literally anything, other than looking at other people’s food, Mistura manned his post. “Fridays were tough,” he said. But he had to do it, on Fridays and every other day too, or the data wouldn’t match. So there he went, day after day, snooping at plates and recording what he saw.

At the time, Mistura was a graduate student in kinesiology, with a focus on behavioural economics and nudge theory, at the University of Victoria. He was watching to see how many students took a vegetable from the hot entrée station at the school’s aging residence cafeteria. His brute manual observation was key to a study aimed at discovering whether behavioural “nudges” could be used to push some the world’s least responsible eaters into making better choices.

For two stretches in the fall term that year, Mistura, under the supervision of Patti-Jean Naylor, an associate professor in the University of Victoria School of Exercise Science, Physical and Health Education, made subtle alterations to the food environment at the hot station. With the co-operation of the food services staff, he had a fresh, raw vegetable option added to the normal cooked vegetable sides that appeared daily in the steam tray. Mistura also added two visual cues to the environment, each designed to prime the minds of the junk-seeking, mostly teenage students.

Above the fresh vegetables, down the row from the hot entrées — lasagna, chicken in mushroom sauce, things of that nature — Mistura placed two signs. One had a smiling green apple in a red headband flexing its very un-apple like biceps between the words “FRESH vegetables” and “Be healthy!” The other had a stalk of broccoli in black sunglasses — a cool broccoli, the kind of broccoli who knows a guy who can hook you up — giving a thumb’s up beneath a message, in green letters, that read:


Health at a great price

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Students are eating a fraction of their required fruit and veggies, research shows. Getty Images

For two weeks before the intervention, Mistura, aided occasionally by a research assistant, recorded both the number of students eating from the hot table during the lunch and dinner rushes and the subsection of those students that selected a hot vegetable. He then repeated the same process with the fresh vegetable option added in, along with the signs, counting both the total number of eaters and the number of vegetable buyers, both hot and cold. He then did the whole process over again, control and intervention, from scratch.

The goal was to see whether the nudges — the fresh, attractive vegetables, usually carrots and celery — and the posters led to a measurable uptick in vegetable selection.

The experiment was one of a series undertaken by Naylor’s grad students aimed at improving the dietary choices of university students. The myth of the freshman 15 (pounds put on) isn’t quite true, Naylor said, but it is grounded in reality. University students who are away from home for the first time and living in residence do tend to put on between 3.5 and 7.5 pounds in their first year. “They leave home. It’s the first time they’re making decisions on their own and they are in a very complex food environment,” Naylor said. “So it’s logical. And yes, there can be some weight gain.”

From a health science point of view the weight isn’t the issue, Naylor said, overall health is. But fruit and vegetable consumption is a key indicator of both and research shows that university-age students are eating just a fraction of the fruits and veggies they need. Naylor’s graduate students have been looking at ways to use behavioural economics to change that. “This is the science of using nudging for public health aims,” Naylor said. “But marketers have used it for years. Some of it just through intuition and doing it. Now, there’s quite a bit of science.”

In one experiment, one of Naylor’s students sent a test group of off-campus students home with special plates designed to subtly prod them toward healthier eating. The images on the plate mimic the rough proportions of a healthy diet. About half the plate features a broccoli forest above blueberries with the message “eat as many fruits and veggies as you’d like!!!” Below the broccoli are smaller pictures of a fish (protein) and slice of bread (whole grains) along with a tiny dot for fat.

This is the science of using nudging for public health aims

The results of that study have yet to be published in a peer-reviewed journal, but Naylor said they were quite promising. The students reported a measurable increase in both fruit and vegetable consumption after taking home the plates.

The results of the cafeteria study, published in August in the journal Nutrients, were a little more mixed. In the first intervention, Mistura recorded a small, but statistically significant increase in vegetable consumption. But when he did the experiment over again a second time, that increase effectively disappeared. “I think I was cautiously optimistic that the nudge probably worked over a very short term, somewhat,” Naylor said.

The experiment took place in the real world, Naylor stressed. It wasn’t a test cafeteria or a lab. And in the real world, “you get a lot of real world problems with evaluation.” For one thing, the nudge only focussed on a single element — the hot table — in a larger cafeteria. It was competing with a host of other behavioural cues, some deliberate, like signs, and others purely environmental, like the smell of French fries or sizzling bacon. “You’re focussing on fruit and veg,” Naylor said. “But you have to remember that’s there’s 10 to 15 nudges going on.”

Mistura, who is now a clinical research co-ordinator at the University of Ottawa Heart Institute, doesn’t regret the weeks and weeks he put in in the cafeteria, standing 2.5 metres from the hot station, watching what the teenagers ate. Nudges are cheap, he believes. Even if they only make a small difference they can be well worth the price. Still, he did express a little bit of disappointment with the results. “I was expecting a little bit more difference,” he said. “I thought the students would be a little more excited.”

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