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NCT Number: NCT05800990

Eating to Adjust the Timing System

The goal of this clinical trial is to test the effects of dietary composition on the rhythms of food intake, appetite regulation, and rhythms of energy expenditure.

Participants will:

complete 2 field-based dietary interventions be provided with standard meals record daily food intake in a real-time manner complete 2 inpatient stays be provided with standard meals have frequent blood draws provide urine, saliva, and stool samples

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Key information

Conditions

Dietary Intervention

Age range

18 year–45 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

About this study

Obesity is an ongoing epidemic and a serious public health problem. Recent insights into the involvement of the circadian system (i.e., an internal biological rhythm) in energy expenditure and appetite control offer a new perspective to understand the relationship between dietary composition and weight management. Particularly, dietary composition may impact whole-body physiology in part through changes in the circadian system. The study protocol is designed to test the effects of dietary composition, on the rhythms of food intake and appetite regulation, and rhythms of energy expenditure. This study seeks to understand the relationship between dietary composition and weight control in order to lay the groundwork for evidence-based dietary intervention to combat obesity.

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • 18-45 yr old
  • BMI 18.5-29.9
  • No acute, chronic or debilitating medical conditions (e.g. metabolic, cardiovascular, respiratory, neurological, cancers, etc.)
  • Without medication use (except oral contraceptives)

Exclusion criteria

  • Currently smoking/vaping or 5 or more years of smoking/vaping
  • History of drug or alcohol dependency
  • History of psychiatric illness or disorder
  • People with food allergies/intolerances or following specific diets

Treatment and study plan

Dietary intervention

Behavioral

Research participants will be assigned to two dietary conditions.

Primary outcomes

  1. Circadian phase of melatonin rhythm

    Time frame: Days 18-19

    Hourly plasma melatonin will be measured under the Constant Routine condition

  2. Percentage of daily caloric intake in the biological evening

    Time frame: Days 8-14

    Percentage of caloric intake within the 4 hours before bedtime will be derived from real-time record of food and beverage intake during the intervention period

Secondary outcomes

  1. Circadian amplitude of melatonin rhythm

    Time frame: Days 18-19

    Hourly circulating melatonin will be measured under the Constant Routine condition

  2. Circadian amplitude of subjective hunger rhythms

    Time frame: Days 18-19

    Hourly subjective hunger will be measured by Visual Analog Scale under the Constant Routine condition

  3. Circadian phase of resting energy expenditure

    Time frame: Days 18-19

    Every other hour energy expenditure will be measured by indirect calorimetry under the Constant Routine condition

Other outcomes

  1. Diurnal variations of postprandial ghrelin responses

    Time frame: Days 17

    Postprandial circulating ghrelin will be measured at test meals on Test Day

  2. Diurnal profile of leptin

    Time frame: Days 17

    Circulating leptin will be measured hourly on Test Day

  3. Diurnal profile of subjective hunger ratings

    Time frame: Day 17

    Hourly subjective hunger will be measured by Visual Analog Scale on Test Day

  4. Circadian amplitude of resting energy expenditure

    Time frame: Days 18-19

    Every other hour resting energy expenditure will be measured by indirect calorimetry under the Constant Routine condition

  5. Diurnal profile of resting energy expenditure

    Time frame: Day 17

    Indirect calorimetry will be done 30 minutes before each test meal and three 30-minute postprandial tests starting at 30, 90, and 240 min after each test meal on Test day by indirect calorimetry

  6. Diurnal profile of respiratory exchange ratio

    Time frame: Day 17

    Respiratory exchange ratio will be measured 30 minutes before each test meal and three 30-minute postprandial tests starting at 30, 90, and 240 min after each test meal on Test Day by indirect calorimetry

  7. Circadian amplitude and phase of respiratory exchange ratio

    Time frame: Days 18-19

    Every other hour respiratory exchange ratio will be measured by indirect calorimetry under the Constant Routine condition

  8. Circadian phase and amplitude of glucose rhythm

    Time frame: Days 18-19

    Hourly circulating glucose will be measured under the Constant Routine condition

  9. Circadian phase and amplitude of insulin rhythm

    Time frame: Days 18-19

    Hourly circulating insulin will be measured under the Constant Routine condition

  10. Circadian phase and amplitude of cortisol rhythm

    Time frame: Days 18-19

    Hourly circulating cortisol will be measured under the Constant Routine condition

  11. Circadian phase and amplitude of core body temperature rhythm

    Time frame: Days 18-19

    Core body temperature will be measured continuously under the Constant Routine condition

  12. Diurnal profile of lipids

    Time frame: Day 17

    Hourly circulating lipids will be measured on Test Day

  13. Circadian phase and amplitude of lipids

    Time frame: Days 18-19

    Hourly circulating lipids will be measured under Constant Routine condition

Study contacts

Contact information is provided by the study sponsor or research team.

Frank A.J.L. Scheer, PhD

CONTACT

[email protected]

617-732-7014

Jingyi Qian, PhD

CONTACT

[email protected]

617-525-7423

Sponsors and collaborators

Lead sponsor

Brigham and Women's Hospital

Other

Collaborators

  • National Institutes of Health (NIH)

Registry information

Official study title

Do Dietary Patterns Influence Your Weight Management and Circadian Rhythms?

Acronym: EATS

Important dates

Study start
2024
Primary completion
2027
Study completion
2027
First posted
Apr 6, 2023
Registry last updated
Sep 29, 2025

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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