Habitual Nightly Fasting Duration, Eating Timing, and Eating Frequency are Associated with Cardiometabolic Risk in Women

Nightly fasting duration (NFD) and eating timing and frequency may influence cardiometabolic health via their impact on circadian rhythms, which are entrained by food intake, but observational studies are limited. This 1-year prospective study of 116 US women (33 ± 12y, 45% Hispanic) investigated associations of habitual NFD and eating timing and frequency with cardiovascular health (CVH; American Heart Association Life's Simple 7 score) and cardiometabolic risk factors. NFD, eating timing and frequency, and nighttime eating levels were evaluated from 1-week electronic food records completed at baseline and 1 y. In multivariable-adjusted linear regression models, longer NFD was associated with poorer CVH (β = -0.22, p = 0.016 and β = -0.22, p = 0.050) and higher diastolic blood pressure (DBP) (β = 1.08, p < 0.01 and β = 1.74, p < 0.01) in cross-sectional and prospective analyses, respectively. Later timing of the first eating occasion at baseline was associated with poorer CVH (β = -0.20, p = 0.013) and higher DBP (β = 1.18, p < 0.01) and fasting glucose (β = 1.43, p = 0.045) at 1 y. After adjustment for baseline outcomes, longer NFD and later eating times were also associated with higher waist circumference (β = 0.35, p = 0.021 and β = 0.27, p < 0.01, respectively). Eating frequency was inversely related to DBP in cross-sectional (β = -1.94, p = 0.033) and prospective analyses (β = -3.37, p < 0.01). In cross-sectional analyses of baseline data and prospective analyses, a higher percentage of daily calories consumed at the largest evening meal was associated with higher DBP (β = 1.69, p = 0.046 and β = 2.32, p = 0.029, respectively). Findings suggest that frequent and earlier eating may lower cardiometabolic risk, while longer NFD may have adverse effects. Results warrant confirmation in larger multi-ethnic cohort studies with longer follow-up periods.