Comparing the effects of time-restricted eating on glycaemic control in people with type 2 diabetes with standard dietetic practice: A randomised controlled trial

Abstract

Aims: To test the efficacy of time-restricted eating (TRE) in comparison to dietitian-led individualised dietary guidance to improve HbA1c in people with Type 2 diabetes mellitus.

Methods: In a parallel groups design, 51 adults (35-65 y) with Type 2 diabetes mellitus and overweight/obesity (HbA1c ≥6.5% (48 mmol/mol), BMI ≥25-≤40 kg/m²) commenced a six-month intervention. Following baseline, participants were randomised to TRE (1000-1900 h) or DIET (individualised dietetic guidance) with four consultations over four months. Changes in HbA1c (primary), body composition, and self-reported adherence (secondary) were analysed using linear mixed models. A non-inferiority margin of 0.3% (4 mmol/mol) HbA1c was set a priori.

Results: Forty-three participants (56 ± 8 y, BMI: 33 ± 5 kg/m², HbA1c: 7.6 ± 0.8%) completed the intervention. HbA1c was reduced (P=0.002; TRE: -0.4% (-5 mmol/mol), DIET: -0.3% (-4 mmol/mol)) with no group or interaction effects; TRE was non-inferior to DIET (-0.11%, 95%CI: -0.50% to 0.28%). Body mass reduced in both groups (TRE: -1.7 kg; DIET: -1.2 kg) via ∼900 kJ/d spontaneous energy reduction (P<0.001). Self-reported adherence was higher in TRE versus DIET (P<0.001).

Conclusions: When individualised dietary guidance is not available, effective, and/or suitable, TRE may be an alternative dietary strategy to improve glycaemic control in people with Type 2 diabetes mellitus.

Keywords: Blood glucose; Chrono-nutrition; Continuous glucose monitoring; Dietitian; Eating window; HbA1c.