Abstract
PURPOSE: To investigate whether dinner dietary intake is associated with subsequent sleep parameters, and whether sleep parameters are associated with subsequent breakfast dietary intake. METHODS: This study used baseline data from the TEMPUS randomized controlled trial. Eligible participants were adults with obesity (30–40 kg/m(2); 25–65 years). Sleep parameters were objectively assessed via accelerometry over 14 days. During this time, dietary intake at dinner and breakfast was assessed using one to two 24 h recalls. Dinner dietary intake was matched with sleep registries of the corresponding night, and sleep parameters with the following breakfast dietary intake. Spearman correlation analyses and linear mixed models were used to assess these relationships. RESULTS: A total of 146 participants (47% women) with valid data were included in the analysis (178 dinner-sleep, and 180 sleep-breakfast observations). Higher carbohydrate, sugars, blue fish, and olive oil intake at dinner were associated with improved subsequent sleep parameters (all p ≤ 0.042). In contrast, greater energy, fat, cholesterol, protein, alcohol, red meat, and french fries were associated with poorer subsequent sleep parameters (all p ≤ 0.048). Longer sleep duration was associated with enhanced dietary quality at subsequent breakfast (all p ≤ 0.034). Moreover, later sleep offset was independently associated with higher energy intake, and greater wake after sleep onset was independently associated with higher carbohydrate intake at subsequent breakfast in multivariate analyses (all p ≤ 0.008). CONCLUSION: These findings highlight the complex relationship between sleep and diet in free-living settings that may inform future interventions for obesity management. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00394-026-03894-z.