Leonie K. Heilbronn

Objective Time‐restricted eating (TRE) restores circadian rhythms in mice, but the evidence to support this in humans is limited. The objective of this study was to investigate the effects of TRE on 24‐hour profiles of plasma metabolites, glucoregulatory hormones, and the subcutaneous adipose tissue (SAT) transcriptome in humans. Methods Men ( n = 15, age = 63 [4] years, BMI 30.5 [2.4] kg/m 2 ) were recruited. A 35‐hour metabolic ward stay was conducted at baseline and after 8 weeks of 10‐hour TRE. Assessment included 24‐hour profiles of plasma glucose, nonesterified fatty acid (NEFA), triglyceride, glucoregulatory hormones, and the SAT transcriptome. Dim light melatonin onset and cortisol area under the curve were calculated. Results TRE did not alter dim light melatonin onset but reduced morning cortisol area under the curve. TRE altered 24‐hour profiles of insulin, NEFA, triglyceride, and glucose‐dependent insulinotropic peptide and increased transcripts of circadian locomotor output cycles protein kaput (CLOCK) and nuclear receptor subfamily 1 group D member 2 (NR1D2) and decreased period circadian regulator 1 (PER1) and nuclear receptor subfamily 1 group D member 1 (NR1D1) at 12:00 am. The rhythmicity of 450 genes was altered by TRE, which enriched in transcripts for transcription corepressor activity, DNA‐binding transcription factor binding, regulation of chromatin organization, and small GTPase binding pathways. Weighted gene coexpression network analysis revealed eigengenes that were correlated with BMI, insulin, and NEFA. Conclusions TRE restored 24‐hour profiles in hormones, metabolites, and genes controlling transcriptional regulation in SAT, which could underpin its metabolic health benefit.