Relaxation of social time pressure reveals tight coupling between daily sleep and eating behavior and extends the interval between last and first meal

Aug 20, 2025Sleep

Less social time pressure links daily sleep and eating closely and lengthens the gap between last and first meal

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Abstract

A 42-minute increase in habitual fasting duration was observed during relaxed social time pressure conditions.

Relaxation of social time pressure during social restrictions led to an average fasting duration increase from 12:16 to 12:57 hours.
The fasting window experienced a delay of 34 minutes, influenced by extended presleep fasting and sleep durations.
Individuals who typically ate breakfast shifted their sleep and fasting times later, while breakfast skippers advanced their meal times.
Ceasing alarm use on workdays correlated with a larger increase in fasting duration.
The relationships between chronotype, fasting duration, and mid-fasting time became stronger during social restrictions.

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STUDY OBJECTIVES: As a day-active species, humans abstain from some or all foods and beverages and rest at night. The modern social clock diverged from the natural light-dark clock with far-stretching consequences for both fasting/eating and sleep/wake daily cycles.

METHODS: During the COVID-19 pandemic, prolonged social restrictions (SRs) offered a quasi-experimental protocol to directly test the impact of the relaxed social clock on eating and sleep behaviors and the coupling between them.

RESULTS: Using data from a global survey of 5747 adults (mean age 37.2 ± 13.7, 67.1% females, 100% worked/studied), we show that relaxation of the social time pressure (STP) during SRs led, on average, to a 42 min increase in the habitual fasting duration (FD, interval between the last and the first meal) (from 12:16 ± 2:09 to 12:57 ± 2:04) and a 34 min delay in the fasting window. FD was extended by lengthening both the presleep fasting and sleep durations. Pre-SR breakfast eaters delayed sleep and fasting, while breakfast skippers delayed sleep and advanced meals. Stopping alarm use on workdays was associated with a larger increase in FD. The correlations between chronotype, FD, and the mid-fasting time became more robust during SR.

CONCLUSIONS: We conclude that relaxed STP extends habitual FD and promotes co-alignment of daily fasting and sleeping. Given the finding that the sleep-fasting phase relationship during SRs remained stable, we suggest that a "daily sleep-fasting structure" may be a novel circadian marker quantifying the coupling between daily rhythms. These results may inform strategies of public circadian health management. Statement of Significance The current study leverages the unique quasi-experimental context of COVID-19 social restrictions (SRs) to reveal a previously unexplored link between social time pressure (STP), daily fasting and sleep in a large, global adult sample from the Global Chrono Corona Survey. We demonstrate that relaxed social schedules induce spontaneous extension of fasting duration and co-alignment of fasting and sleep rhythms. During SRs, the sleep-fasting phase relationship was stable, despite substantial shifts in meal and sleep timings. These findings unveil the role of STP in shaping daily rhythms, with broad implications for metabolic and sleep health. The daily sleep-fasting structure can serve as a novel marker for future research and interventions aimed at optimizing circadian health outcomes in modern societies.

Key numbers

42 min

Increase in Fasting Duration

Average increase in habitual fasting duration pre- vs. during lockdowns

34 min

Delay in Mid-Fasting Time

Average delay in mid-fasting time during lockdowns

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Relaxation of social time pressure reveals tight coupling between daily sleep and eating behavior and extends the interval between last and first meal

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