B01

Metabolic disorders are closely linked to sleep disturbances. Timerestricted eating (TRE) can improve metabolic disturbances, but its impact onsleep quality is insufficiently studied and recommendations regarding the eatingtiming in TRE are pending. Our aim was to investigate the impact of early TRE(eTRE) and late TRE (lTRE) on sleep quality in obesity. This is a secondary analysis of the randomized crossover trial, whichincluded 31 women with overweight and obesity. Following a 2–4 week baselineperiod, participants were assigned to either a two-week eTRE (eating 8a.m−4p.m.) or a two-week lTRE (eating 1 p.m.−9 p.m.), separated by a two-weekwashout phase. Sleep metrics were assessed objectively by blinded actigraphyand subjectively using Pittsburgh Sleep Quality Index (PSQI) and self-reportof sleep quality. Hunger and satiety were examined using a Visual AnalogueScale (VAS). Actigraphy revealed no between-intervention differences in changesin sleep metrics, but improvements were observed within eTRE compared withbaseline for sleep efficiency (p = 0.047), sleep fragmentation index (SFI) (p= 0.029), and awakening length (p = 0.043). Individuals with lowest sleepquality at the baseline showed its largest improvements in eTRE. PSQI scoresand self-reported sleep quality remained unchanged between and within bothinterventions. There were no differences in evening hunger and satiety scoresbetween eTRE and lTRE, and no correlations between hunger or satiety andsleep quality

Time-restricted eating (TRE) is a promising strategy against metabolic disorders, but its effects on lipid metabolism remain controversial. The present research assesses and compares the impact of early (eTRE) versus late (lTRE) TRE on the plasma lipidomic profile. This is an exploratory outcome of the previously published randomized crossover trial, which examines 31 women with overweight or obesity who follow a two-week eTRE and a two-week lTRE in an intended isocaloric setting. Blood plasma and subcutaneous adipose tissue biopsies are analyzed using shotgun lipidomics and transcriptomics, respectively. Between interventions and within the lTRE, lipid species and classes, as well as enzyme activity indices, are not substantially changed. Within the eTRE, changes are observed for 103 lipid species, including a reduction of ceramide and phosphatidylcholine classes, and for the desaturation indices D5D, D6D, and D9D, as well as the elongation index ELOVL6. Combined analysis of plasma lipidome and adipose tissue reveals alterations in the glycerophospholipid pathway and in the expression of phospholipase enzymes PLB1, PLA2G6, and PLAG4B, dependent on TRE timing. These results suggest that eating timing during TRE may be crucial for remodeling the plasma lipidome and adipose tissue transcriptome and highlight the need of future lipidomic research in TRE.