Associations of time-restricted eating with health-related quality of life and sleep in adults: a secondary analysis of two pre-post pilot studies

Background: Therapeutic fasting may improve health-related quality of life (HRQoL) and sleep but is not applicable for everyone. Time-restricted eating (TRE) offers a low threshold alternative but research on associations with HRQoL and sleep is rare. Methods: We conducted a secondary analysis of two pilot studies in a pre-post design, which examined TRE in healthy employees at the Ulm University and in abdominal obese patients in a general practitioners office. Participants reported their HRQoL (EQ-5D visual analogue scale) before and after 3 months of restricting their daily eating to 8-9 h. They kept a diary to protocol timing of first and last meal, sleep quality (analogue scale) and duration. Pearson's correlation coefficient was applied to test bivariate correlations between continuous variables and linear regression analyses were conducted to identify associated factors with the pre-post differences in HRQoL and the differences in sleep quality. Results: Ninety-nine participants (aged aged 48.9 +/- 1.1, 83.8% female) reached the fasting target of 15-16 h on average on 77.2 +/- 18.7% of all recorded days. HRQoL increased by 7.8 +/- 12.6 and sleep quality by 9.6 +/- 13.9 points, but sleep duration was not extended. Regression analysis revealed mean fasting duration and baseline sleep quality as significant factors associated with changes in HRQoL. Improvements in sleep quality correlated with baseline sleep quality and HRQoL at follow-up but not with fasting. Changes in anthropometry did not correlate with the HRQoL or sleep quality. Conclusions: TRE correlates with increased HRQoL and sleep quality independent from weight loss. TRE is easily applicable with or without medical supervision. The potential effects of TRE on health and sleep should be further investigated in larger randomized trials.