Effects of early vs. late time-restricted eating on 24-hour glucose profiles and internal circadian time

Aims Time-restricted eating (TRE) is a promising strategy to improve metabolic outcomes but there is a lack of carefully controlled trials. We investigated whether timing of the eating window affects diurnal rhythms of circadian clock and glucose and improves glycemic control in subjects with an increased diabetes risk upon a stable body weight.

Methods In a randomized cross-over trial, 31 overweight or obese non-diabetic women (58.4±1.5y; 30.5±0.5kg/m2) followed a two-week eTRE (eating 8a.m.-4p.m.) and two-week lTRE (eating 1p.m.-9p.m.) being asked to consume their usual food quality and quantity. Glycemic control was assessed by continuous glucose monitoring (CGM) followed by analysis of glycemic indices and glucotypes (a novel method of glucose variability quantification). Internal circadian time was assessed by the BodyTime assay in isolated blood monocytes.

Results Study subjects showed a high timely compliance, unchanged dietary composition, minor daily calorie deficit (eTRE:-167kcal) and weight reduction (eTRE:-1.1kg, lTRE:-0.4kg). We found an advancing circadian phase by 40 min after the lTRE compared to the eTRE. The 24-hour glucose profiles were also shifted accordingly to the eating timing. CGM-derived fasting and postprandial glucose was increased during the lTRE compared to baseline. However, mean 24h glucose levels, mean amplitude of glycemic excursion (MAGE), and glucotypes were not changed by both TRE interventions. Mean of daily difference (MODD) index slightly decreased during both eTRE (p=0.037) and lTRE (p=0.003).

Conclusion Upon a nearly stable body weight, both eTRE and lTRE do not clinically relevantly alter glycemic control despite significant changes of circadian systems in non-diabetic subjects.

Publication History

Article published online:
02 May 2023