Sleepy People Make Bad Food Choices

Sleepy People Make Bad Food Choices

june 13 2012
By Ed Susman, Contributing Writer, MedPage

Reviewed by Dori F. Zaleznik, MD; Associate Clinical Professor of Medicine, Harvard Medical School, Boston and Dorothy Caputo, MA, BSN, RN, Nurse Planner
BOSTON – Getting a good night's sleep might mean you will pass on the cheeseburger the next day, sleep researchers suggested here at the annual meeting of the Associated Professional Sleep Societies.

Laboratory experiments with healthy volunteers indicate that people who experience sleep deprivation undergo brain changes that make them susceptible to making poorer dietary choices, said researchers, noting that functional magnetic resonance imaging (fMRI) scans correlated with areas in the brain that influence integrated decision-making -- that is, the ability to determine if eating a doughnut was not only rewarding and tasty but also healthy.


When Stephanie Greer, a graduate student at the Helen Wills Neuroscience Institute Sleep and Neuroimaging Laboratory at the University of California Berkeley, scrutinized fMRI studies of the ventral striatum – the area of the brain that is linked to rewards – she found no statistically significant differences between the sleep-deprived and the sleep-rested individuals.

But when she looked at the insula, cingulate, and orbitofrontal areas of the brain, there were strong differences in which areas were enhanced among individuals who were sleep-rested. All these differences were statistically significant (P<0.05), she demonstrated. "We did not find significant differences following sleep deprivation in brain areas traditionally associated with basic reward reactivity," Greer said in her oral presentation. "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." Greer enrolled 23 healthy subjects into a crossover study, 13 of whom were women. All the subjects were of normal weight and had no restrictions on food and no food allergies. They had no history of neurological, psychiatric, or sleep disorders. The healthy volunteers were assigned to a well-rested period from 11 p.m. to 8 a.m. and then at 9:30 a.m. underwent the fMRI study. The other group stayed up all night, were offered a snack at 2:30 a.m., breakfast at 8:30 a.m. and then the fMRI. In the fMRI, the subjects were asked about their desires for certain foods – whether they wanted or didn't want them. And then the results were analyzed. In the second part of the study the roles were reversed. In a second report, Scott Wolfe, MS, clinical coordinator at the New York Obesity Nutrition Research Center, enrolled 12 men and 13 women into his sleep deprivation study. The subjects were about 34 years of age, had normal weights and body mass indices. Excluded from the study were individuals who smoked or who had diabetes, neurological diseases, and other conditions. In this study, the individuals spent 6 days on restricted sleep – 4 hours – or had normal rest periods of 9 hours. After a three-week washout period, they returned to the sleep unit and their roles were reversed. While in the sleep unit their meals were controlled for 4 days and then they were allowed to make their own food choices in the next 2 days. After 6 days the subjects were then given fMRI testing. The anterior cingulate cortex is correlated with total sleep deprivation and appetite, Wolfe noted. In his study, he found that activation of sleep-deprived individuals "was similar to that of the obese" as shown in other studies. "In the sleep-deprived state, unhealthy foods activate the areas of the brain more involved in addiction and cognitive controls," Wolfe said in his oral presentation. "Restricting sleep can increase salience of unhealthy food. This may explain the observed effect on an increased preference for high-fat and high-sugar food after sleep restriction." While the studies may point to areas that can use additional research, Sanjay Patel, MD, lecturer on medicine at Beth Israel Deaconess Medical Center, Brigham & Women's Hospital/ Harvard Medical School, in Boston, told MedPage Today that use of healthy volunteers as subjects in the studies may not relate to people who are obese or diabetic. "I'm not really sure how relevant these studies are. They bring people in the lab for 2 weeks and they put food in front of them. So everyone overeats. That's not how we live in real life." Patel also suggested that by excluding patients who are obese or diabetic, the researchers may be testing the wrong population. "The positive findings are relevant as being hypothesis-generating to see if this works out in real life," he said. "The negative study may be negative because they are studying the wrong people."