Interaction between Meal-timing and Dietary Inflammatory Potential: Association with Cardiometabolic Endpoints in a 3-month Prospective Analysis.

Background: Diet quality is a moderator of cardiometabolic markers. The timing of dietary intake may be an important determinant; however, previous results have been mixed. Complex mechanisms may result in an interaction between diet timing and quality.

Objectives: This study aimed to examine the association between fasting duration and first and last mealtime and inflammatory and lipid biomarkers. We also explored the interactions between Energy-density Dietary Inflammatory Index (E-DII) scores and meal-timing on inflammatory and lipid biomarkers.

Methods: This study was a secondary data analysis of a dietary intervention. Assessments occurred at baseline and 3-months. Three unannounced 24-hour dietary recalls estimated diet for calculation of E-DII scores, nighttime fasting duration, and first and last mealtime. Cardiometabolic markers were obtained from a fasting blood sample. Multiple linear regression of baseline data was used for Aim 1. For Aim 2, the interaction between E-DII change over 3 months and the meal-timing metrics were used to estimate changes in cardiometabolic markers.

Results: Most participants (n=95) were female (81%) and White (62%) and they had an average age of 46.9 ± 13.4 years and BMI of 31.4 ± 7.1 kg/m. Every one-hour longer fasting duration was associated with increased total cholesterol (β=5.79, p=0.01), LDL-cholesterol (β=4.47, p=0.03), and LDL:HDL ratio (β=0.08, p=0.04). For every 30-minute later first mealtime, increases in total cholesterol, LDL-cholesterol and LDL:HDL ratios also were observed. Anti-inflammatory E-DII changes were associated with reduced total cholesterol and LDL-C (among participants with shorter fasting durations, later last mealtime, or earlier first mealtime) and C-reactive protein (CRP, among earlier first mealtime and shorter fasting duration).

Conclusions: This study provides evidence for interaction between dietary timing and quality on cardiometabolic biomarkers. Worsening lipid profiles seen with longer fasting durations may be an artifact of skipped or delayed breakfast, underlining the potential importance of food consumption early in the morning.

Gov Identifier: NCT02382458 (https://clinicaltrials.gov/ct2/show/NCT02382458).