Your coworker forgot to finish her part of the project and you're scrambling to complete the PowerPoint before the deadline. It's just a little stressful. No, biggie, right? Well, it might be wrecking your resistance more than you thought.
A study in Neuron shows that moderate stress erodes a person's willpower, causing them to head straight for the junk food.
“Self-control is a tricky problem: almost everybody has good intentions when it comes to making a decision that requires self-control — you want to do the right thing,” Silvia Maier, a doctoral candidate in neuroeconomics at the University of Zurich and one of the study’s authors, told TODAY via email. “Yet from experience we all know that these intentions do not always lead to actions that go along with our best interest.”
Silvia and Todd Hare, assistant professors of neuroeconomics, designed the study to understand why stressed-out people struggle with self-control.
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They asked 51 men interested in diet and exercise to rank 70 foods on their healthiness and tastiness. The researchers chose to study men because their cortisol levels — a stress hormone — are more stable than women’s.
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Twenty-nine of the participants were then asked to put their hands in cold water, a technique that induces stress.
Afterward, all the participants underwent a functional MRI (fMRI), a brain scan to monitor stress levels. During the process, each participant was asked to indicate what he wanted to eat; and each was told he would get one of his wishes when the process was over. The 29 participants who experienced stress were more likely to choose junk foods — chips, crackers, chocolate, cookies, cake, ice cream — while the other 22 less-stressed folks preferred fruits, vegetables, bread, cereal and yogurt.
“Food choices are a good example to investigate how people trade off certain features of choice options against each other,” Maier said. “We felt it was important to examine how stressors that are a part of daily life influence the brain and self-control choices.”
The fMRI images allowed the researchers also to understand how the brain communicates when it’s stressed. The study reinforced what other research found in the past—the ventromedial prefrontal cortex (vmPFC) evaluates all the options and shares this information with the brain. But when someone’s stressed out, the striatum and amygdala increase their chatter to the vmPFC. The striatum and amygdala play up the tastiness of the food, making it harder for the brain to resist the junk.
“You could say it’s almost like stress is turning up the dial on signals about taste, and turning down the signal on health,” said Maier.
Understanding how the brain copes with stress means researchers are better able to help people cope with stress and bolster willpower.
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“Once we understand how the brain changes its decision processes in response to stress, we can design better interventions,” said Maier.
According to her, it’s important for people to be aware of their stress and try to cope with it in healthy ways. One way to avoid stress eating is to pre-commit.
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Pre-committing is when people remove temptations before they become temptations. Instead of just saying you won't eat too much junk food, you never buy it, so it is easier to avoid the problem. This helps support your willpower.
“Going to the corner shop to satisfy a craving is much less likely than going to the cupboard in your kitchen to grab a cookie or bag of potato chips,” says Maier.
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Or you can boost willpower by imagining the temptation, not the reward (such as sweetness), before you confront it.
"Previous findings indicate that it’s crucial to think about the hurdle, the means to overcome it, and the reward in this order; putting imagining the reward first can actually increase the likelihood to fail," says Maier.
This story was originally published in August 2015.