Compliance and Tolerability of a 16-Hour Prolonged Nighttime Fasting Regimen in Healthy Males: a Preliminary Study

Abstract

Background: Prolonged nighttime fasting is a type of intermittent fasting that may be a more maintainable method for 
improved health as compared to caloric restriction. This study aimed to determine the compliance and tolerability of a 4-week 
16-hour nighttime fasting regimen.Methods: Compliance and tolerability were assessed though a post-study survey and a compliance diary. Pre- and post-study health and longevity biomarkers were also assessed. Additionally, dietary intake was evaluated using the Automated SelfAdministered 24-Hour Recall and physical activity using the International Physical Activity Questionnaire.
Results: All 11 subjects completed the prolonged fasting nighttime regimen. The mean fasting time was 16.5 hours, with 
an average of 2.4 days of noncompliance. Survey results confirmed tolerability, with no perceived changes in quality of life, 
sleep, physical activity, or daily tasks. The regimen did not significantly impact any health parameters or biomarkers assessed, 
except for a reduction of systolic blood pressure (p=0.03) and increased antioxidant capacity in the blood (p=0.001). Diastolic 
blood pressure tended to decrease, but did not reach statistical significance (p=0.05)Conclusion: Prolonged nighttime fasting may be a maintainable variation of intermittent fasting, as the subjects in this study were able to comply with the regimen and believed it to be tolerable