(P25-099-20) An Effectiveness Study of Early or Late Time-Restricted Feeding on Body Composition – Pilot Study

Objectives: Our objective was to measure the differences in body composition change following a 6-week early or late time-restricted feeding without specific calorie-targets in healthy but sedentary free-living individuals with overweight/obesity.

Methods: Sedentary, healthy individuals with a body mass index (BMI) of more than 25kg/m² were recruited for a 6-week intervention. They were randomized to morning fasters (MF) who ate only between 12 pm to 8 pm, evening fasters EF who ate only between 7 am and 3 pm; and the control group, which was instructed to continue their usual pattern of eating. Specific calorie targets were not provided to all participants. Pre- and post-intervention height and weight were measured, and body composition was assessed using the dual-energy x-ray absorptiometry scanner. Intention to treat analysis was performed, using the last observation carried forward. Normality was assessed. Between-group differences in change of body composition and within-group differences for pre- and post-measurements were studied using parametric and non-parametric tests accordingly, and Bonferroni correction for multiple testing was applied.

Results: 10, 8, and 10 participants were in the MF, EF, and control groups, respectively. There were 11 males and 17 females. The mean age of our participants was 30.25 (SD=10.99) years and mean BMI was 29.06 (SD = 3.63)kg/m2. There was no difference in baseline age, BMI, body fat percent, total body fat mass, total lean mass and visceral fat between the 3 groups (p >0.05). Compliance was significantly lower in evening fasters than controls (p=0.029). Unlike MF, EF had a greater reduction in body fat mass than the controls, but the difference was non-significant (p=0.053). There were no significant differences in body composition pre-vs post measurements within each study group (p >0.05).

Conclusions: When specific calorie targets were not provided, morning fasting and evening fasting did not result in a significant change in body composition in sedentary adults with overweight/ obesity in our pilot study. A larger-scale study is needed to validate these findings.

Funding Sources: Startup funds from Texas Tech University