Fiber and Saturated Fat Are Associated with Sleep Arousals and Slow Wave Sleep.
Level 2 - randomized trial
Randomized crossover inpatient trial with observational regression analysis
PubMed 26156950 · doi:10.5664/jcsm.5384
What was done
Twenty-six normal-weight adults (aged 30–45 years, habitual sleep 7–9 h/night) participated in an inpatient randomized-crossover study. Data from the habitual sleep phase (9 hours in bed) were analyzed. Participants consumed a controlled diet for the first 4 days and self-selected ad libitum food on day 5. Sleep architecture was compared between controlled and ad libitum feeding, and linear regression was used to relate day 5 nutrient intake to nocturnal sleep.
What was found
Sleep duration did not differ between controlled feeding and ad libitum intake. Ad libitum eating resulted in less slow wave sleep (SWS, P = 0.0430) and longer sleep onset latency (P = 0.0085). Greater fiber intake predicted less stage 1 sleep (P = 0.0198) and more SWS (P = 0.0286). A higher percent of energy from saturated fat predicted less SWS (P = 0.0422). Higher percent of energy from sugar (P = 0.0320) and other carbohydrates (P = 0.0481) was associated with more arousals. Absolute numbers for sleep stages and intake were not reported in the abstract.
Why it matters
This paper demonstrates that single-day variations in macronutrient quality—specifically fiber, saturated fat, and sugar—are linked to objective sleep architecture and nighttime arousals in healthy adults.
Limits
The sample size was small (n = 26) and restricted to healthy, normal-weight adults. Macronutrient associations were evaluated via regression on a single day of ad libitum intake rather than randomized nutritional interventions for each specific nutrient.