Researchers have found that a challenging morning may affect a person's decision to eat more indulgently at lunch.

In a study published in the journal Neuron, researchers subjected volunteers in a similar scenario to explore how stress can change the brain, impairing self-control and influencing food choices. Silvia Maier, the study's lead author, said that their findings showed a crucial step towards clearly understanding interactions that occur between self-control and stress in the brain, with effects affecting multiple neural pathways.

"Self-control abilities are sensitive to perturbations at several points within this network, and optimal self-control requires a precise balance of input from multiple brain regions rather than a simple on/off switch," she added, emphasizing that a lot of research still needs to be done, however, to completely understand the involved mechanisms.

For the study, the researchers worked with 29 subjects who underwent a laboratory treatment that induces moderate stress by immersing their hands in icy water for three minutes. Another group of 22 were also included in the study but they did not undergo the lab treatment. Both sets of subjects were made to choose between food items, with the first group doing so after their treatment.

All the subjects for the study were actively making efforts to stick to a healthy lifestyle so working with the researchers presented a conflict they are familiar with: making the choice to eat something very tasty but unhealthy or something less tasty but healthy.

According to the results of the study, the researchers discovered that the two groups chose food differently, suggesting that experiencing a stressful event (the ice bath treatment, in this case) made the subjects lean towards favoring taste over how healthy a food item is.

Additionally, this effect was physically manifested in the brains of the subjects from the stressed-out group. Particularly, the participants exhibited altered brain patterns in connections between regions, including the ventromedial prefrontal cortex, dorsolateral prefrontal cortex, striatum and amygdala, with the alterations reducing the subjects' abilities to exercise self-control over the food choices they were making. Only a small portion of the brain changes observed can be associated with cortisol.

The researchers said that knowing moderate stress can have an effect on self-control is important because moderately stressful events are more common than their extreme counterparts and affect a bigger chunk of the population.

One focus that future research can explore will be determining whether factors that can protect against structural brain changes after severely stressful events can also be used to alleviate the effects of moderate stress.

Photo: Luis Tamayo | Flickr

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