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Completed

NCT Number: NCT07451132

Time-restricted Eating and Circadian Health in Night Shift Workers

The goal of this clinical trial is to learn about the effect of time-restricted eating (TRE) to 10 hours per day on glucose homeostasis, markers of the circadian system, homeostatic and hedonic regulation of appetite, and inflammation/oxidative stress status in night shift workers. The main questions it aims to answer are: 1) How does a time-restricted eating protocol affect glucose homeostasis in shift workers? and 2) How does a time-restricted eating protocol affect markers of the circadian system, homeostatic and hedonic regulation of appetite, and inflammation/oxidative stress status in shift workers? Participants will be asked to follow a TRE protocol on which they must restrict their eating to a self-selected time window of 10 hours a day, with mandatory fasting time between 24:00-06:00h. for 8 weeks. Researchers will compare the intervention with an additional period of 8 weeks, in which the participants will follow their usual diet without any time restriction, to see if the intervention improves glucose regulation appetite and markers of circadian system, homeostatic and hedonic regulation of appetite, and inflammation/oxidative stress.

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Key information

Conditions

Intermittent Fasting in Shift-work Behavior Fasting Feeding Behavior Intermittent Fasting

Age range

18 year–60 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Faculty of Medicine, University of Chile

Santiago, Metropolitan Region, 8380453, Chile

About this study

This is a randomized, crossover, controlled, within-subject study. After recruitment, participants will be randomized to one of two conditions: i) Time-restricted eating (TRE), with an eating window of 10 hours per day but without any other diet modification (e.g., types of food or amount of energy consumed). Each participant can freely choose the starting time of their eating window. If a participant need to make modifications to the start time of their eating window, he/she may do so only once during the TRE period, and the research team must be informed. After a washout period of at least 30 days, participants will undergo ii) Regular eating (REG), during which the participants must maintain their usual eating pattern (i.e., usual eating window), without making any dietary or lifestyle changes. Each condition will have a duration of 8 weeks. Randomization will be done using computer-generated random numbers.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Adults (range 18 - 60 yrs.) Men and women Performing as a healthcare worker Being a shift-worker for at least 6 months in the current schedule Working in rotating shiftwork, including at least one night shift Reporting no work-related performance difficulties

Exclusion criteria

  • Current and chronic neurological disorders
  • Pathologies related to abnormal adrenal activity
  • Liver or kidney disease
  • Uncontrolled hypertension, dyslipidemia, and thyroid disease
  • Insulin resistance and T2D
  • BMI ≥40 kg/m2
  • Use of medications known to alter body composition, such as insulin sensitizers, glucocorticoids, or anti-depressants
  • Autoimmune diseases with acute symptoms; recent surgery of any kind (in the last 3 months);
  • Acute, chronic inflammation (usCRP >10 mg/L)
  • Following any dietary restriction (special diet) in the previous three months
  • Having a short sleep (habitual sleep duration of less than 6h per day)
  • History of bariatric surgery
  • Depression (Beck Depression Inventory) or sleep disorders (Pittsburgh Sleep Questionnaire)
  • Night-eating syndrome (Night Eating Questionnaire)
  • Intense exercise level (>3 days/week of high-intensity exercise)
  • Having traveled across time zones (at any time during the last month) and planning travel during the study
  • Pregnant or intend to become pregnant, and
  • Lactating women

Treatment and study plan

Time-restricted eating

Behavioral

During the intervention (TRE) each participant will freely choose the starting time of their eating window. If needed, participant can modify the selected start time of their eating window only once during the intervention period, and the research team must be informed. After a washout period of at least 30 days, participants will undergo the opposite condition (TRE or Regular eating) after the initial randomization

Primary outcomes

  1. Change from Baseline in the mean fasting glycemia at 8 weeks

    Time frame: From baseline to the end of treatment (at 8 weeks), in each study period (TRE and REG)

    Fasting glycemia level (in mg/dL) will be measured from fasting blood samples and measured with the hexokinase method

Secondary outcomes

  1. Change from baseline to end of treatment (8weeks) in 24-h glycemic control

    Time frame: From baseline to the end of treatment (at 8 weeks), in each study period (TRE and REG)

    24-h glycemic control (expressed in mg/dL), measured with continuous glucose monitoring (CGM) using a portable capillary glucose sensor, over 10 consecutive days.

  2. 24-hour motor activity level (counts/min)

    Time frame: From enrollment to the end of treatment (at 8 weeks), in each study period (TRE and REG)

    Motor activity will be assessed by accelerometric recordings (actigraphic data) of wrist activity. Actigraphy data will assess motor activity before and after the intervention

  3. Change from Baseline in the circadian clock-genes expression at 8 weeks

    Time frame: From baseline to the end of treatment (at 8 weeks), in each study period (TRE and REG)

    Clock-gene expression will be evaluated by relative expression, performing RT-stem loop real-time PCR, from fasting whole-blood samples taken at baseline and after 8 weeks, in each study period. Gene expression levels of the target sequences will be normalized to the expression of GAPDH, and will be calculated by applying equation 2-∆∆ CT.

  4. Change from baseline in thiobarbituric acid reactive substances (TBARS) level at 8 weeks

    Time frame: From baseline to the end of treatment (8 weeks) in each study period (TRE and REG)]

    TBARS level (in µM/ml) will be measured in plasma samples

  5. Change from baseline in F-8 isoprostane level at 8 weeks

    Time frame: From baseline to the end of treatment (8 weeks) in each study period (TRE and REG)

    F-8 isoprostane level (in pg/mL) will be measured in plasma samples

  6. Change from Baseline in Appetite-related feelings at 8 weeks

    Time frame: From baseline to the end of treatment (8 weeks) in each study period (TRE and REG)

    A visual analog scale will be used to assess appetite feeling levels. Each participant rates their subjective feelings of appetite, satiety, and desire to eat using a 100 mm visual analog scale, with endpoints indicating from "not at all" (0 mm) to "extremely" (100 mm).

  7. Change from baseline in total-, reduced- and oxidized glutathione levels at 8 weeks

    Time frame: From baseline to the end of treatment (8 weeks) in each study period (TRE and REG)

    Total-, reduced-, and oxidized glutathione levels (in µM) will be measured in plasma samples

  8. Change from baseline in C-reactive protein levels at 8 weeks

    Time frame: From baseline to the end of treatment (8 weeks) in each study period (TRE and REG)

    C-reactive protein levels (in mg/L) will be measured in serum samples

  9. Change from baseline in pro-inflammatory cytokine levels at 8 weeks

    Time frame: From baseline to the end of treatment (8 weeks) in each study period (TRE and REG)

    Interleukin 1β, Interleukin 6, and Tumor necrosis factor (TNF-α) levels (in pg/mL) will be measured in plasma samples.

Other outcomes

  1. Change in body mass index at 8 weeks

    Time frame: From baseline to the end of treatment (8 weeks) in each study period (TRE and REG)

    Body mass index will be calculated (expressed as kg/m2) from body weight and height anthropometric measurements, measured with light clothes and expressed as Kg (weight) and cm (height), respectively.

  2. Change from baseline in fat mass index at 8 weeks

    Time frame: From baseline to the end of treatment (8 weeks) in each study period (TRE and REG)

    Fat mass index (in kg/m²) will be assessed by dual-energy X-ray absorptiometry (DXA) using a Lunar DPXL densitometer

  3. Change from Baseline in sleep duration at 8 weeks

    Time frame: From baseline to the end of treatment (8 weeks) in each study period (TRE and REG)

    Sleep duration will be measured through continuous actigraphic recordings during daytime and nighttime for 10 days, and expressed in minutes

  4. Change from baseline in fat-free mass index at 8 weeks

    Time frame: From baseline to the end of treatment (8 weeks) in each study period (TRE and REG)

    Fat-free mass index (in kg/m²) will be assessed by dual-energy X-ray absorptiometry (DXA) using a Lunar DPXL densitometer

  5. Change from baseline in fat mass at 8 weeks

    Time frame: From baseline to the end of treatment (8 weeks) in each study period (TRE and REG)

    Fat mass (in %) will be assessed by dual-energy X-ray absorptiometry (DXA) using a Lunar DPXL densitometer

  6. Change from baseline in muscle mass at 8 weeks

    Time frame: From baseline to the end of treatment (8 weeks) in each study period (TRE and REG)

    Muscle mass (in %) will be estimated by dual-energy X-ray absorptiometry (DXA) using a Lunar DPXL densitometer

  7. Change from baseline in Bone Mineral Density at 8 weeks

    Time frame: From baseline to the end of treatment (8 weeks) in each study period (TRE and REG)

    Bone Mineral Density (BMD, in g/cm2) will be assessed by dual-energy X-ray absorptiometry (DXA) using a Lunar DPXL densitometer

Sponsors and collaborators

Lead sponsor

University of Chile

Other

Collaborators

  • Agencia Nacional de Investigación y Desarrollo

Registry information

Official study title

Effect of a Time-restricted Eating Protocol on Glucose Homeostasis, Markers of Circadian System, Appetite Control, and Oxidative Stress Parameters in Night Shift Workers

Acronym: FastingClocks

Important dates

Study start
2023
Primary completion
2025
Study completion
2025
First posted
Mar 5, 2026
Registry last updated
May 13, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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