The relationship of quantity and quality of carbohydrate intakes with sleep quality: a cross sectional study

Sleep quality is crucial for daily functioning and health, and diet, particularly carbohydrate (CHO) intake, is a modifiable influence. Existing research on CHO and sleep is limited and often contradictory. This study investigated the association between carbohydrate quality/quantity and sleep quality. A cross-sectional study included 1904 participants. Food intake was assessed using a 106-item semi-quantitative food frequency questionnaire (FFQ), capturing percentage of energy intake from CHO, total dietary fiber, Dietary Glycemic Index (DGI), Dietary Glycemic Load (DGL), whole grain/total grain intake, and fiber/total CHO intake. Sleep quality was evaluated using the Pittsburgh Sleep Quality Index (PSQI). Binary and ordinal regression analyses were performed. The population (45% male) had a mean age of 39.63 ± 10.24 years and BMI of 27.08 ± 4.91 kg/m 2 . Higher fiber intake was associated with better overall sleep quality (e.g., third tertile vs. first: 35% lower odds of bad overall sleep quality; 95% CI: 0.47–0.91), subjective sleep quality, and reduced sleep onset latency. Higher fiber/total CHO intake correlated with better subjective sleep quality. Increased percentage of energy intake from CHO was linked to reduced sleep medication. Conversely, higher DGL was associated with increased odds of daytime dysfunction. Both quantity and quality of carbohydrate intake significantly relate to sleep quality. Higher dietary fiber intake is linked to some better sleep outcomes, higher DGL may impair daytime function and lower sleep medication usage associate to higher CHO intake. While our findings reveal significant associations, the cross-sectional design precludes conclusions regarding causality, necessitating longitudinal or interventional studies for definitive insights.