The results of a new study showed that higher fat intakes were associated with increased daytime sleepiness, and higher carbohydrate intakes caused an increase in vigilance in humans. However, no association was found between protein intake and sleepiness. These conclusions were made regardless of gender, age, body mass index, as well as the total amount of sleep of research objects, scientists took into account only their total calorie intake.

“Increasing fat intake has an acute negative impact on the alertness of healthy, non-obese adults,” said principal investigator Alexandros Vgontzas, M.D., professor of psychiatry at Penn State College of Medicine in Hershey, Pennsylvania. The main group consisted of 31 healthy, non-obese people, aged 18-65, who spent four consecutive nights in the laboratory. On the fourth day, target sleepiness was assessed using a specific test.

Previous studies have found that dietary composition subjectively affects sleepiness, the researchers said. “It seems that a diet with a high fat content significantly reduces vigor, and this can affect a person’s ability to work, as well as his public safety,” said Alexandros. The results of the study were recently published in the online journal Sleep and Alexandros presented his findings in Baltimore, Maryland, at the 27th annual meeting of LLC Professional Societies.