The Fasting and Shifted Timing (FAST) of Eating Study: A pilot feasibility randomized crossover intervention assessing the acceptability of three different fasting diet approaches

Background and aims: The aim of this study is to assess the acceptability of following three different fasting protocols [Early Time-restricted Feeding (eTRF; eating majority of kcals before 5pm), Time-restricted Feeding (TRF; restricting feeding window to 8 h/d), or Alternate Day Fasting (ADF; complete fasting every other day)]. Methods: In this remotely delivered six-week crossover intervention, participants were randomly assigned to follow either an eTRF, TRF, or ADF diet for one week, followed by a one-week washout period. Participants followed all three diets and completed questionnaires assessing self-reported weight, energy intake, dietary acceptability (Food Acceptability Questionnaire), and facilitators and barriers to adhering to each diet. Differences in main outcomes (e.g., dietary acceptability and weight loss) were assessed via repeated measures ANOVA. Results: A total of 32 of participants began the study (mean BMI of 32.6 +/- 6.0 kg/m(2)). There were no differences in kcals or weight loss among the three diets. Dietary acceptability was higher on the TRF diet (54.1 +/- 8.2) than the eTRF (50.2 +/- 6.6, p = 0.02) or ADF (48.0 +/- 7.9, p = 0.004) diets. The majority of participants (71%) indicated the TRF diet was the easiest to follow and 75% said that ADF was the most difficult. Participants cited having a mobile app to track their diet and being provided with menu plans would help facilitate adherence with their diets. Conclusions: This study found that acceptability was highest for an TRF diet and lowest for ADF, with no differences in weight loss or change in energy intake among the TRF, ADF, or eTRF groups.

Automated summary

This study aimed to assess the acceptability of three different fasting protocols. The results showed that the Time-restricted Feeding (TRF) diet had the highest acceptability, while the Alternate Day Fasting (ADF) diet had the lowest. There were no significant differences in weight loss or energy intake among the three diets. Participants mentioned that using a mobile app to track their diet and being provided with menu plans would help with adherence to their diets.