Intended isocaloric time-restricted eating shifts circadian clocks but does not improve cardiometabolic health in women with overweight

Oct 29, 2025Science translational medicine

Time-restricted eating with equal calories changes daily body clocks but may not improve heart and metabolism health in overweight women

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Abstract

In a trial involving 31 women, neither early time-restricted eating (eTRE) nor late time-restricted eating (lTRE) improved insulin sensitivity or other cardiometabolic traits.

Insulin sensitivity did not significantly differ between eTRE and lTRE or within each intervention.
No clinically meaningful differences were observed in 24-hour glucose, lipid, inflammatory, and oxidative stress markers.
Participants adhered well to the eating schedules, with 96.5% adherence for eTRE and 97.7% for lTRE.
A minor daily calorie deficit was noted during eTRE (-167 kilocalories/day) with a weight loss of -1.08 kilograms.
Circadian phase shifts were observed, with a later timing in blood monocytes and sleep midpoint for lTRE compared to eTRE.

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Time-restricted eating (TRE) is a promising strategy to improve metabolic outcomes. However, it remains unclear whether TRE has cardiometabolic benefits in an isocaloric setting and whether its effects depend on the eating timing. We conducted a randomized crossover trial in 31 women with overweight or obesity to directly compare the effects of a 2-week early TRE (eTRE; eating from 8:00 to 16:00) and a 2-week late TRE (lTRE; eating from 13:00 to 21:00) on insulin sensitivity, cardiometabolic risk factors, and the internal circadian phase. During the restricted 8-hour eating period, participants were asked to consume their habitual food quality and quantity. Insulin sensitivity did not differ between (-0.07; 95% CI, -0.77 to 0.62; = 0.60) or within (eTRE: 0.31; 95% CI, -0.14 to 0.76; = 0.11; lTRE: 0.19; 95% CI, -0.22 to 0.60; = 0.25) interventions. Twenty-four-hour glucose, lipid, inflammatory, and oxidative stress markers showed no clinically meaningful between- or within-intervention differences. Participants demonstrated high timely adherence (eTRE, 96.5%; lTRE, 97.7%), unchanged dietary composition and physical activity, minor daily calorie deficit (eTRE, -167 kilocalories/day), and weight loss (eTRE, -1.08 kilograms; lTRE, -0.44 kilograms). In lTRE, the circadian phase in blood monocytes (24 minutes; 95% CI, -5 to 54 minutes; = 0.10) and sleep midpoint (15 minutes; 95% CI, 7 to 23 minutes; < 0.001) occurred later compared with eTRE. Overall, in an intended isocaloric setting, neither eTRE nor lTRE improves insulin sensitivity or other cardiometabolic traits, despite a shift of internal circadian clocks. P P P P P