A new study published in the journal Obesity has shown that unhealthy diets may impair deep sleep and negatively impact its restorative properties.
The crossover study featured 15 healthy young men. In a random order, participants were given a “healthy” diet or an “unhealthy” diet for one week while their sleep was monitored. After consuming the first diet, each participant switched to the other diet for one week while their sleep continued to be monitored. Each diet contained the same number of calories, but the unhealthy diet featured more sugar, more unsaturated fat, and more processed foods.
The results of the sleep monitoring study showed that participants slept for the same amount of time after consuming each diet, and they also spent the same amount of time in each sleep stage regardless of what they ate. However, participants who had just eaten the unhealthy diet showed less slow-wave activity during deep sleep, which is a measure of how restorative the sleep is. Notably, similar changes to deep sleep can occur with aging as well as with sleep disorders such as insomnia.
One of the authors noted that poor diets and poor sleep patterns are both associated with serious public health conditions. In particular, heart health is tied to both sleep and diet, and an increased risk of heart disease occurs when either factor is worsened. The authors further noted that they did not identify a particular molecule or nutrient that negatively impacts sleep, which may be a topic of further study. The current diets of many Americans contain higher levels of sugar, saturated fat, and processed foods than those examined in the study, which is likely to negatively impact sleep and has potential to worsen memory and other cognitive functions.