PurposePrevious literature highlights the need to examine the intersection between nutrition and circadian biology. This study examined the association between meal-timing (i.e., fasting duration and first and last mealtime) and cardiometabolic endpoints (i.e., inflammatory and lipid markers), and examined the interactive effects between the Energy-density Dietary Inflammatory Index (E-DII) and meal-timing on cardiometabolic endpoints. MethodsThis was a secondary data analysis of a 3-month anti-inflammatory diet intervention. Three unannounced 24-hour dietary recalls estimated diet for calculation of the E-DII, nighttime fasting duration, and first and last mealtime. A fasting blood draw was used to estimate the cardiometabolic markers. Multiple linear regression was used to address the study aims with inclusion of interactions between meal-timing and the E-DII. ResultsParticipants (n = 95) were primary female (81%) and White (62%). The average body mass index was 31.4 ± 7.1 kg/m2 and average age was 46.9 ± 13.4years. Every 1-hour increase in fasting duration was associated with increased total cholesterol (β = 5.79, P = .01) LDL-cholesterol (β = 4.47, P = .03), and LDL:HDL (β = 0.08, P = .04). The same was true for every 30-minute increase in first mealtime. Anti-inflammatory E-DII changes were associated with reduced total cholesterol (among shorter fasting durations or later last mealtime), LDL-cholesterol (among later last mealtime), and C-reactive protein (among earlier first mealtime). ConclusionsThis study provides some evidence for interactive effects between dietary timing and quality on cardiometabolic biomarkers. Worsening lipid profiles seen with longer fasting durations may be an artifact of delayed or skipped breakfast, further stressing the importance of food consumption early in the morning.