Altered carbohydrate and protein intake may affect sleep quality

1. In this systematic review, long-term increased carbohydrate intake improved rapid eye movement (REM) sleep, and higher protein diets had poor effects on sleep.

2. Furthermore, caloric restriction alongside higher protein diet had positive sleep effects for overweight and obese individuals.

Evidence Rating Level: 2 (Good)

Poor sleep quality is associated with significant health morbidity. It has been noted that sleep and nutrition have a bidirectional relationship. Macronutrient manipulation has been commonly applied among popular weight loss diets. This study’s goal was to characterize the literature surrounding macronutrient changes in an individual’s diet, and the effects this may have on quality of sleep.

The study was a systematic review completed under PRISMA guidelines that searched for articles with sleep and diet terms.. Inclusion criteria consisted of studies that delivered any macronutrient intervention, included human participants, and measured some form of subjective or objective sleep measure. Studies that were non-English, pediatric, or animal-based were excluded. The Cochrane Risk of Bias tool was applied to assess the quality of studies. 1909 records were identified, 1680 articles were subsequently screened, and 28 were eligible for full-text analysis.

17 articles were included in a thematic analysis. Three macronutrient manipulation types were identified in the study that include acute intervention (less than 24 hours), longer-term manipulation, and macronutrient changes with energy restriction. Seven studies showed that longer-term manipulation of carbohydrates negatively affect non-REM sleep, but positively improves REM sleep. Furthermore, protein intake at the recommended amount reduced wake episodes; however, increased intake showed increased restlessness and wake time. Interestingly, amongst obese and overweight individuals, high protein diets with energy restriction had a positive impact on sleep. Finally, three studies regarding lipid intake manipulation were inconclusive in their effect. In summary, this study was limited by the heterogeneity of the studies as there was a variety of diet comparators. In addition, macronutrient intake differs greatly based on bioavailability, gastric emptying, and nutrient metabolism within each macronutrient. Nonetheless, this study was significant in beginning to to elucidate the relationship between sleep and macronutrient alteration.

Click to read the study in Nutrition and Dietetics 

Image: PD

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