Cognitive decline is intricately linked to various factors such as obesity, stress, poor sleep, and circadian rhythm misalignment, which are interrelated in their impact on cognitive health. Irregular food-intake timing further compounds these issues. The practice of prolonged nightly fasting (PNF) may help synchronize food intake with circadian rhythms, potentially mitigating adverse effects of cognitive decline and associated factors.

A pilot nationwide, remotely delivered, 2-arm randomized controlled trial was conducted to assess the 8-week outcomes of cognition, stress, and sleep, after a PNF intervention (14-hr nightly fast, 6 nights/week, no calories after 8 pm) compared to a health education (HED) control condition. Participants were living with memory decline, stress, and obesity and had weekly check-in calls to report fasting times (PNF) or content feedback (HED).

Participants were enrolled from 37 states in the US; N = 58, 86% women, 71% white, 93% non-Latinx, mean (SD) age 50.1 (5.1) years and BMI 35.6 (3.6) kg/m2. No group differences existed at baseline. Linear mixed-effects models were used to compare outcome change differences between groups. Compared to the HED control, the PNF intervention was associated with improved sleep quality (B = −2.52; SE = 0.90; 95% CI −4.30–−0.74; p = 0.006). Perceived stress and everyday cognition significantly changed over time (p < 0.02), without significant difference by group.

Changing food intake timing to exclude nighttime eating and promote a fasting period may help individuals living with obesity, memory decline, and stress to improve their sleep. Improved sleep quality may lead to additional health benefits.