Can't stay alert? Your diet may be to blame

New research suggests that your level of sleepiness or alertness during the day may be directly related to the type of food you eat. The study, led by Alexandros Vgontzas, MD, professor of psychiatry at the Penn State College of Medicine in Hershey, Pa., aimed to look at how fat, carbohydrate and protein consumption affected objective daytime sleepiness and alertness in healthy, non-obese subjects without sleep apnea.

Researchers recruited 31 healthy, non-obese, 'normal' sleepers between the ages of 18-65 to spend four consecutive nights in a sleep lab. On the fourth day, the participants’ diets and objective sleepiness were assessed using the Multiple Sleep Latency Test (MSLT), a diagnostic tool used to measure the time elapsed from the start of a designated nap period to the first signs of sleep.

The results showed that higher fat consumption was associated with increased objective daytime sleepiness, while higher carbohydrate intake was associated with increased alertness. Protein consumption did not affect sleepiness or alertness.

“Increased fat consumption has an acute adverse effect on alertness of otherwise healthy, non-obese adults,” said Vgontzas.

Vgontzas further implies that high-fat diets could also have a negative lifestyle impact: “Excessive daytime sleepiness and fatigue are very prevalent in the modern world and on the rise. It appears that a diet high in fat decreases alertness acutely, and this may have an impact on an individual’s ability to function and also public safety.”