Effects of Different Types of Intermittent Fasting Interventions on Metabolic Health in Healthy Individuals (EDIF): A Randomised Trial with a Controlled-Run in Phase

Abstract

The effects of intermittent fasting (IF) on health promotion in the healthy population remain controversial. Therefore, our study aimed to analyse the efficacy and feasibility of different IF protocols and evaluated the effects within a cohort with a controlled-run in phase on the body mass index (BMI) as the primary outcome, the body composition, and metabolic and haematological markers in healthy participants. A total of 25 individuals were randomised into three fasting groups: 16/8 fasting (n = 11), 20/4 fasting (n = 6), and alternate-day fasting (ADF, n = 8). Assessments were conducted at baseline (visit 1), after a four-week controlled-run in phase (visit 2), and after eight weeks of fasting (visit 3). Both the BMI (p = 0.01) and bodyweight (p = 0.01) were significantly reduced in the ADF group, which was not seen in the 16/8 and 20/4 groups (p > 0.05). Adherence was different but not statistically among the groups (16/8: 84.5 ± 23.0%; 20/4: 92.7 ± 9.5%; and ADF: 78.1 ± 33.5%, p = 0.57). Based on our obtained results, the data suggest that some fasting interventions might be promising for metabolic health. However, adherence to the specific fasting protocols remains challenging even for the healthy population.

Keywords: anthropometry; body mass index; metabolism; time-restricted feeding; weight loss.

Figure 1

Study flow chart of the EDIF trial, including a controlled-run in phase of four weeks (visit 1 to visit 2) and an interventional phase follow-up of eight weeks (visit 2 to visit 3) after randomisation to the three IF intervention groups: 16/8 fasting, 20/4 fasting, and ADF. Abbreviations: BIA = bioelectrical impedance analysis.

Figure 2

Flow chart considering study-specific features. Abbreviations: 16/8 = fasting for 16 h and eating for the remaining 8 h as time-restricted feeding periods; 20/4 = fasting for 20 h and eating for the remaining 4 h as time-restricted feeding periods; ADF = alternate-day fasting; BMI = body mass index.

Figure 3

Δ BMI differences of the respective groups during the fasting periods. ns: not significant (p > 0.05). p-value: * statistically significant (p < 0.05). Abbreviation: BMI = body mass index.