Sleepless Nights From Munchies

Sleep deprivation may make it harder for people to choose the best foods to eat

(RxWiki News) Sometimes the simplest decisions, such as what to have for lunch, are more complicated than they should be. This may be especially true after a night of no sleep.

Did you know that the part of the brain related to decision making may not function properly when a person hasn't had enough sleep?

This can be especially true when it comes to making choices about food. A recent small and unpublished study presented at a sleep conference used brain scans to show how insufficient sleep may lead to inappropriate food choices.

"Tell your doctor if you aren't sleeping enough."

Lead author Stephanie Greer -- a graduate student at the Sleep and Neuroimaging Laboratory at the University of California, Berkeley -- and colleagues conducted a study to find out how certain regions of the brain related to food processing changed following a period of sleep deprivation.

The researchers also considered whether or not people took different factors into account when selecting food at these times.

The study surveyed 23 healthy adults aged 18 to 25. They were then given two functional MRI images: once after a normal's night's sleep and once after not sleeping for 24 hours. The normal night's sleep meant the participants were provided a nine hour window to sleep, though most averaged around eight hours.

During each scan, the participants rated how much they wanted each of 80 different foods on a scale of one to four. They then rated how healthful they thought each food item was and how tasty it was on a scale of one to four.

Greer wanted to find out how likely a person was to want food if they knew it was healthy - even after a night without sleep.

"We saw a significant drop in the percentage of participants who took health into account when they were sleep deprived," Greer told dailyRx.

The participants also didn't take tastiness as much into account in their desire for food items when they were sleep deprived, though the drop was not as great as that for the healthfulness ratings of the food.

While the participants were well rested, 52 percent of them took the perceived healthfulness of a food into account and 100 percent of them took taste into account when deciding if they wanted it. This was measured by correlating their scores on their desire for the food with their rankings on its healthfulness and taste.

But after a night of sleep deprivation, only 17 percent of them wanted the food they perceived to be healthy, and 86 percent of them wanted the foods that were tastiest.

"They had difficulty integrating important food signals into account when they were sleep deprived," Greer said.

Matthew Walker, PhD, Greer's graduate advisor and a coauthor on the paper, said the results showed that fewer participants were using the healthiness of the food to inform what they wanted to eat when they were sleep deprived.

The fMRI scans supported this disconnect between what a person should want and what they actually wanted. The results showed that the brain activity was abnormal in specific areas of the front lobe known from previous research to be involved in controlling behavior and making complex decisions.

The researchers interpreted the results to mean that a person's higher brain functions - such as those used for making these decisions about what to eat - may be hampered after not having enough sleep.

"We did not find significant differences following sleep deprivation in brain areas traditionally associated with basic reward reactivity," Greer said. "Instead, it seems to be about the regions higher up in the brain, specifically within the frontal lobe, failing to integrate all the different signals that help us normally make wise choices about what we should eat."

In other words, as Walker pointed out, the sleep deprivation did not lead the participants to make food choices based on perceived rewards, such as the taste of the food, based on the activity seen in the scans.

Instead, it simply prevented the participants from being able to take into account how healthy or tasty the food was in deciding if they wanted it.

"These results shed light on how the brain becomes impaired by sleep deprivation, leading to improper food choices," Greer said.

The study was presented June 10 at the 26th annual meeting of the Associated Professional Sleep Societies in Boston. Because the study has not yet been published in a peer-reviewed journal, its results should be regarded as preliminary and still require review by researchers in the field.

The research was funded by the National Institutes of Health. No conflicts of interest were noted.

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Review Date: 
June 8, 2012