Eating to Adjust the Timing System (EATS)

Do Dietary Patterns Influence Your Weight Management and Circadian Rhythms?

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

Study Overview

• Status: Recruiting
• Conditions: Dietary Intervention
• Intervention / Treatment: Behavioral: dietary intervention

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Estimated): 24
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Jingyi Qian, PhD; Phone Number: 617-525-7423; Email: jqian@bwh.harvard.edu
• Study Contact Backup: Name: Frank A.J.L. Scheer, PhD; Phone Number: 617-732-7014; Email: FSCHEER@BWH.HARVARD.EDU

Study Locations

• United States
  • Massachusetts
    • Boston, Massachusetts, United States, 02115
      • Recruiting
      • Brigham and Women's Hospital
      • Principal Investigator: Frank A.J.L. Scheer, PhD
      • Contact: Arman Arab, PhD; Phone Number: 617-278-0703; Email: aarab1@mgb.org
      • Contact: Rahul Reddy, Bsc; Phone Number: 617-525-8259; Email: rmreddy@bwh.harvard.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 45 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Dietary A-B Intervention; The Dietary A first, then the Dietary B intervention. Since this is a single blind study, the details of the dietary interventions cannot be released during recruitment stage but will be made public once enrollment closes.	Behavioral: dietary intervention; Research participants will be assigned to two dietary conditions.
Experimental: Dietary B-A Intervention; The Dietary B first, then the Dietary A intervention. Since this is a single blind study, the details of the dietary interventions cannot be released during recruitment stage but will be made public once enrollment closes.	Behavioral: dietary intervention; Research participants will be assigned to two dietary conditions.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Circadian phase of melatonin rhythm	Hourly plasma melatonin will be measured under the Constant Routine condition	Days 18-19
Percentage of daily caloric intake in the biological evening	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	Days 8-14

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Circadian amplitude of melatonin rhythm	Hourly circulating melatonin will be measured under the Constant Routine condition	Days 18-19
Circadian amplitude of subjective hunger rhythms	Hourly subjective hunger will be measured by Visual Analog Scale under the Constant Routine condition	Days 18-19
Circadian phase of resting energy expenditure	Every other hour energy expenditure will be measured by indirect calorimetry under the Constant Routine condition	Days 18-19

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Diurnal variations of postprandial ghrelin responses	Postprandial circulating ghrelin will be measured at test meals on Test Day	Days 17
Diurnal profile of leptin	Circulating leptin will be measured hourly on Test Day	Days 17
Circadian phase and amplitude of glucose rhythm	Hourly circulating glucose will be measured under the Constant Routine condition	Days 18-19
Circadian phase and amplitude of insulin rhythm	Hourly circulating insulin will be measured under the Constant Routine condition	Days 18-19
Circadian phase and amplitude of cortisol rhythm	Hourly circulating cortisol will be measured under the Constant Routine condition	Days 18-19
Circadian phase and amplitude of core body temperature rhythm	Core body temperature will be measured continuously under the Constant Routine condition	Days 18-19
Diurnal profile of lipids	Hourly circulating lipids will be measured on Test Day	Day 17
Circadian phase and amplitude of lipids	Hourly circulating lipids will be measured under Constant Routine condition	Days 18-19
Diurnal profile of subjective hunger ratings	Hourly subjective hunger will be measured by Visual Analog Scale on Test Day	Day 17
Circadian amplitude of resting energy expenditure	Every other hour resting energy expenditure will be measured by indirect calorimetry under the Constant Routine condition	Days 18-19
Diurnal profile of resting energy expenditure	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	Day 17
Diurnal profile of respiratory exchange ratio	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	Day 17
Circadian amplitude and phase of respiratory exchange ratio	Every other hour respiratory exchange ratio will be measured by indirect calorimetry under the Constant Routine condition	Days 18-19

Collaborators and Investigators

• Sponsor: Brigham and Women's Hospital
• Collaborators: National Institutes of Health (NIH)
• Investigators: Principal Investigator: Frank AJL Scheer, PhD, Brigham and Women's Hospital

Study record dates

Study Major Dates

• Study Start (Actual): November 8, 2024
• Primary Completion (Estimated): August 31, 2027
• Study Completion (Estimated): August 31, 2027

Study Registration Dates

• First Submitted: March 24, 2023
• First Submitted That Met QC Criteria: March 24, 2023
• First Posted (Actual): April 6, 2023

Study Record Updates

• Last Update Posted (Estimated): September 29, 2025
• Last Update Submitted That Met QC Criteria: September 25, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Keywords: circadian rhythm; energy expenditure; appetite regulation
• Additional Relevant MeSH Terms: Therapeutics; Nutrition Therapy; Diet Therapy
• Other Study ID Numbers: 2023P000622

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No