Effects of Early and Late Time-Restricted Feeding on Parameters of Metabolic Health: An Explorative Literature Assessment

Abstract

Chrono-nutrition (meal timing) aligns food consumption with one's circadian rhythm. The first meal (e.g., breakfast) likely promotes synchronization of peripheral circadian clocks, thereby supporting metabolic health. Time-restricted feeding (TRF) has been shown to reduce body weight (BW) and/or improve cardiovascular biomarkers. In this explorative literature assessment, 13 TRF randomized controlled trials (RCTs) were selected from PubMed and Scopus to evaluate the effects of early (eTRF: first meal before 10:30 a.m.) and late TRF (lTRF: first meal after 11:30 a.m.) on parameters of metabolic health. Although distinct variations in study design were evident between reports, TRF consistently decreased energy intake (EI) and BW, and improved insulin resistance as well as systolic blood pressure. eTRF seemed to have a greater beneficial effect than lTRF on insulin resistance (HOMA-IR). Importantly, most studies did not appear to consider chronotype in their evaluation, which may have underestimated TRF effects. TRF intervention may be a promising approach for risk reduction of human metabolic diseases. To conclusively determine benefits of TRF and identify clear differences between eTRF and lTRF, future studies should be longer-term (≥8 weeks) with well-defined (differences in) feeding windows, include participants chronotypically matching the intervention, and compare outcomes to those of control groups without any dietary limitations.

Keywords: TRE; TRF; chronotype; insulin resistance; metabolic health; overweight; randomized controlled trial; time-restricted feeding; weight loss.

Figure 1

Diagram showing the grouping of study arms and their comparisons (Δ). A total of 13 intervention studies were included. Two studies compared eTRF and lTRF [28,29]; 2 studies compared eTRF, lTRF and control [30,31]; 7 studies compared eTRF and control [34,38,39,40,41,42,43]; and 2 studies compared lTRF and control [32,33]. This resulted in 4 Δ (eTRF-lTRF) [28,29,30,31], 9 Δ (eTRF-control) [30,31,34,38,39,40,41,42,43], and 4 Δ (lTRF-control) [30,31,32,33].

Figure 2

Comparisons (Δ) of the changes in (A) fasting glucose levels, (B) fasting insulin levels, (C) HOMA-IR, (D) energy intake, (E) body weight, (F) triglycerides, (G) LDL cholesterol, (H) total cholesterol, (I) HDL cholesterol, and (J) systolic blood pressure between eTRF, lTRF, and/or control groups. Each bar represents the difference between two arms: orange Δ (eTRF-lTRF), green Δ (eTRF-control), and blue Δ (lTRF-control); [number] is the study reference, * p < 0.05 [28,29,30,31,32,33,34,38,39,40,41,42,43].

Figure 2

Comparisons (Δ) of the changes in (A) fasting glucose levels, (B) fasting insulin levels, (C) HOMA-IR, (D) energy intake, (E) body weight, (F) triglycerides, (G) LDL cholesterol, (H) total cholesterol, (I) HDL cholesterol, and (J) systolic blood pressure between eTRF, lTRF, and/or control groups. Each bar represents the difference between two arms: orange Δ (eTRF-lTRF), green Δ (eTRF-control), and blue Δ (lTRF-control); [number] is the study reference, * p < 0.05 [28,29,30,31,32,33,34,38,39,40,41,42,43].