Junk food almost twice as distracting as healthy food

October 26, 2017

Science Daily/Johns Hopkins University

When we haven't eaten, junk food is twice as distracting as healthy food or non-food items.

Even when people are hard at work, pictures of cookies, pizza and ice cream can distract them -- and these junk food images are almost twice as distracting as health food pictures, concludes a new Johns Hopkins University study, which also found that after a few bites of candy, people found junk food no more interesting than kale.

The study, which underscores people's implicit bias for fatty, sugary foods, and confirms the old adage that you shouldn't grocery shop hungry, is newly published online by the journal Psychonomic Bulletin and Review.

"We wanted to see if pictures of food, particularly high-fat, high-calorie food, would be a distraction for people engaged in a complicated task, said co-author Howard Egeth, a professor in the Department of Psychological and Brain Sciences. "So we showed them carrots and apples, and it slowed them down. We showed them bicycles and thumb tacks, and it slowed them down. But when we showed them chocolate cake and hot dogs, these things slowed them down about twice as much."

First, Egeth and lead author Corbin A. Cunningham, Distinguished Science of Learning Fellow in the Department of Psychological and Brain Sciences, created a complicated computer task, in which food was irrelevant, and asked a group of participants to find the answers as quickly as possible. As the participants worked diligently, pictures flashed in the periphery of the screen -- visible for only 125 milliseconds, which is too quick for people to fully realize what they just saw. The pictures were a mix of images of high-fat, high-calorie foods, healthy foods, or items that weren't food.

All of the pictures distracted people from the task, but Cunningham and Egeth found things like doughnuts, potato chips, cheese and candy were about twice as distracting. The healthy food pictures -- like carrots, apples and salads -- were no more distracting to people than non-foods like bicycles, lava lamps and footballs.

Next, the researchers recreated the experiment, but had a new group of participants eat two fun-sized candy bars before starting the computer work.

The researchers were surprised to find that after eating the chocolate, people weren't distracted by the high-fat, high-calorie food images any more than by healthy foods or other pictures.

The researchers wonder now if less chocolate or even other snacks would have the same effect.

"I assume it was because it was a delicious, high-fat, chocolatey snack," Egeth said. "But what if we gave them an apple? What if we gave them a zero-calorie soda? What if we told the subjects they'd get money if they performed the task quickly, which would be a real incentive not to get distracted. Could junk food pictures override even that?"

Cunningham said the results strikingly demonstrate that even when food is entirely irrelevant, and even when people think they're working hard and concentrating, food has the power to sneak in and grab our attention -- at least until we eat a little of it.

"What your grandmother might have told you about not going to the grocery store hungry seems to be true," Cunningham said. "You would probably make choices that you shouldn't or ordinarily wouldn't."

https://www.sciencedaily.com/releases/2017/10/171026135327.htm

Brain Scans Show Specific Neuronal Response to Junk Food When Sleep-Restricted

June 10, 2012

Science Daily/American Academy of Sleep Medicine

The sight of unhealthy food during a period of sleep restriction activated reward centers in the brain that were less active when participants had adequate sleep, according to a new study using brain scans to better understand the link between sleep restriction and obesity.

Researchers from St. Luke's -- Roosevelt Hospital Center and Columbia University in New York performed functional magnetic resonance imaging (fMRI) on 25 men and women of normal weights while they looked at images of healthy and unhealthy foods. The scans were taken after five nights in which sleep was either restricted to four hours or allowed to continue up to nine hours. Results were compared.

"The same brain regions activated when unhealthy foods were presented were not involved when we presented healthy foods," said Marie-Pierre St-Onge, PhD, the study's principal investigator. "The unhealthy food response was a neuronal pattern specific to restricted sleep. This may suggest greater propensity to succumb to unhealthy foods when one is sleep restricted."

Previous research has shown that restricted sleep leads to increased food consumption in healthy people, and that a self-reported desire for sweet and salty food increases after a period of sleep deprivation. St-Onge said the new study's results provide additional support for a role of short sleep in appetite-modulation and obesity.

"The results suggest that, under restricted sleep, individuals will find unhealthy foods highly salient and rewarding, which may lead to greater consumption of those foods," St-Onge said. "Indeed, food intake data from this same study showed that participants ate more overall and consumed more fat after a period of sleep restriction compared to regular sleep. The brain imaging data provided the neurocognitive basis for those results."

http://www.sciencedaily.com/releases/2012/06/120610151447.htm