Eating a high-fat and high-sugar diet results in worsening of quality of deep sleep, according to findings of a new study from Uppsala University in Sweden published in the journal Obesity^.1

In this crossover study, 15 healthy normal-weight young men were randomized to either a high-fat/high-sugar diet or a low-fat/low-sugar diet for a period of one week each. The study objective was to examine the influence of food on sleep patterns in healthy individuals. After each week, the sleep pattern was recorded in the laboratory via polysomnography during a full night of sleep and during recovery sleep after extended wakefulness. Sleep duration, stages (macrostructure) and sleep microstructure (oscillatory patterns and slow waves) were examined.

There are four stages of sleep: non-rapid eye movement (NREM) sleep with the N1, N2, and N3 stages and one rapid eye movement (REM) sleep. The N3 stage is deep sleep and is the most rejuvenating. The NREM and REM phases occur in a cyclical manner, 4 to 6 times.

Results showed that the duration of sleep as determined by actigraphy and in-lab polysomnography remained the same with both groups. After one week on each diet, the structure of sleep also continued to be the same. But when the two diets were compared, the high fat and high sugar diet was found to be associated with decreased delta power, delta to beta ratio and slow wave amplitude but increased alpha and theta power during deep sleep. Similar changes were also observed during recovery sleep.

These findings suggest a link between unhealthy high fat and high sugar diet and deep sleep quality.

Although the small sample size is a limitation of the study, nevertheless, it highlights how one’s lifestyle can affect sleep. A healthy diet has a positive impact on overall health and well-being.

Last year, the American Heart Association (AHA) added sleep to Life’s Simple 7, its checklist for a healthy heart. The new “Life’s Essential 8” includes 4 health behaviors (diet, physical activity, nicotine exposure, sleep) and 4 health factors (BMI, cholesterol, blood sugar, and blood pressure).

Reference

1. Luiz Eduardo Mateus Brandão, et al. Exposure to a more unhealthy diet impacts sleep microstructure during normal sleep and recovery sleep: A randomized trial. Obesity (Silver Spring). 2023 May 28. doi: 10.1002/oby.23787.