Prolonged nightly fasting in older adults with memory decline: A single-group pilot study exploring changes in cognitive function and cardiometabolic risk factors.

Introduction: Older age significantly increases risk for cognitive decline. A growing number of older adults (≥ 65 years) experience cognitive decline that compromises immediate and/or long-term health. Interventions to mitigate cognitive decline are greatly needed. Intermittent fasting aligned with innate circadian rhythms is associated with health benefits and improved circadian rhythms; here, we explore impacts on cognition and cardiometabolic outcomes.

Methods: We conducted a single-group, pre-/post-pilot study to explore an 8-week prolonged nightly fasting intervention (14 h fasting/night) among adults 65+ years with self-reported memory decline. We explored changes in cognitive function, insomnia, and cardiometabolic risk factors. Intervention engagement/adherence were assessed. The intervention was delivered fully remotely; participants completed their fasting protocol at home and were not required to come into the lab.

Results: In total, 20 individuals signed consent and 18 participants completed the study. Participants were mean age 69.7 years, non-Hispanic White (89%), predominantly female (95%), married (50%), and employed (65%). Paired t-tests indicated an increase in cognitive function (Memory and Attention Phone Screener) (p = 0.02) with a medium effect size (Cohen's d = 0.58) and a decrease in insomnia (Insomnia Severity Index) (p = 0.04) with a medium effect size (Cohen's d = 0.52). Changes in BMI or diet quality were not observed. Engagement (66%-77%) and adherence (70%-100%) were high.

Conclusion: These pilot findings suggest that prolonged nightly fasting, targeted to align food intake with circadian rhythms, may improve cognitive function and sleep among older adults. Fully powered, randomized controlled trials to test the efficacy of this non-pharmacological, low cost-to-burden ratio intervention are needed.