Overweight and ObesityTime2EatNCT05870982
Early vs. Late Time Restricted Eating vs. Daily Caloric Restriction
A study testing Early TRE, Late TRE and DCR in people with Overweight and Obesity, run by University of Colorado, Denver at 1 site in United States.
Trial summary
The goal of this clinical trial is to learn about time restricted eating as a weight loss intervention in adults with obesity. The main questions it aims to answer are: 1. How does the timing of the eating window (early vs late time restricted eating) affect weight loss and changes in metabolic risk factors? 2. Read more about this study
- Who is it for?
- Ages 18 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Overweight and Obesity
- What is being tested?
- Early TRE, Late TRE and DCR
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 162 participants
- Where
- 1 siteUnited States
- Study dates
- 11 Jul 2023to Sep 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Adult males and females with a BMI of 27-45 kg/m2
- Age, 18-65 years old
- Passing medical and physical screening, and analysis of blood and urine screening samples
- Individuals who are not currently following an intermittent fasting or TRE dietary regimen (i.e., eating across less than a 10-hour period during the day).
- Own a smartphone
- Live or work within 45 minutes of the Anschutz Health \& Wellness Center (exceptions may be made at the discretion of the Study PI on a case-by-case basis for highly motivated subjects)
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- No plans to relocate within the next 12 months
- Capable and willing to give informed consent, understand exclusion criteria, and accept the randomized group assignment.
- Have a primary care physician (or are willing to establish care with a primary care physician prior to study enrollment) to address medical issues which may arise during screening or study procedures/interventions.
Who cannot join
- Pregnancy or lactation for women (women who are >6 months postpartum with no plans of becoming pregnant in the next year and who are not currently lactating can be included; oral contraceptives will be allowed if medication has been consistent for the prior 6 months)
- Weight loss >5kg in past 3 months for any reason except post-partum weight loss, weight gain >5kg in past 3 months requires assessment by PI to determine reason for weight gain and if it is appropriate for the subject to participate in the study
- Weight loss of >50 lbs in past 3 years for any reason except post-partum weight loss
- Presence or history of any metabolic or chronic health problems which would affect appetite, food intake, energy metabolism, or ability to optimally participate in the exercise component including: CVD, peripheral vascular disease, cerebrovascular disease, significant cardiac arrhythmias or cardiac valve disease, diabetes, uncontrolled hyper- or hypothyroidism, uncontrolled hypertension, cancer (within the last 5 years, except skin cancer or other cancers considered cured with excellent prognosis), HIV infection, seizure disorders, significant gastrointestinal disorders (described below), significant pulmonary disorders (described below), significant renal, musculoskeletal, neurologic, hematologic, or psychiatric disease.
- Significant gastrointestinal disorders including: chronic malabsorptive conditions, peptic ulcer disease, Crohn's disease, Ulcerative Colitis, chronic diarrhea, or active gallbladder disease.
- Significant pulmonary disorders including: chronic obstructive pulmonary disease (COPD), interstitial lung disease, cystic fibrosis, or uncontrolled asthma.
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- Symptoms suggestive of CVD: chest pain, shortness of breath at rest or with mild exertion, syncope.
- Taking medications affecting weight or energy intake/energy expenditure in the last 6 months, including weight loss medications, antipsychotic drugs or other medications as determined by the study physician
- Having abnormal blood chemistry (eGFR<45mL/min, AST or ALT >3 times the upper limit of normal) or as deemed significant by the study physician
- LDL cholesterol >200 mg/dL
- Triglycerides > 500 mg/dL
- Being considered unsafe to participate as determined by the study physician
- Previous obesity treatment with surgery or weight loss device, except: (1) liposuction and/or abdominoplasty if performed > 1 year before screening, (2) lap banding if the band has been removed > 1 year before screening, (3) intragastric balloon if the balloon has been removed > 1 year before screening (4) duodenal-jejunal bypass sleeve, if the sleeve has been removed > 1 year before screening or 5) AspireAssist or other endoscopically placed weight loss device if the device has been removed > 1 year before screening.
- Being a smoker or having been a smoker in the 3 months prior to their screening visit
- Working night shifts
- Night eating syndrome (at least 25% of food intake is consumed after the evening meal and/or at least two episodes of nocturnal eating per week) as assessed with meal pattern assessment questionnaire
- History of clinically diagnosed eating disorders including anorexia nervosa, bulimia, binge eating disorder. Score >20 on the EATS-26, score of >27 on the BES, or pattern of response on the QEWP-5 suggestive of possible binge eating disorder or bulimia will require further assessment by the Study MD to determine if it is appropriate for the subject to participate in the study.
- Current alcohol or substance abuse (assessed with CAGE-AID questionnaire (48))
- Current severe depression or history of severe depression within the previous year, based on DSM-IV-TR criteria for Major Depressive Episode. Score > 18 on BDI will require further assessment by the Study MD to determine if it is appropriate for the subject to participate in the study.
- Individuals who are already following an intermittent fasting or TRE dietary regimen and individuals not willing to abstain from alcohol outside of prescribed eating windows will also be excluded.
- Currently participating in or planning to participate in any formal weight loss or physical activity programs or clinical trials
- Regular use of systemic steroids (other than oral contraceptive pills)
- Medication(s) that must be taken with food (PI discretion based on whether it would be feasible for the participant to take the medication with food in the afternoon or evening if assigned to L-TRE group)
- Currently participating in a weight loss program or research study or participation in a weight loss program or research study within 1 year prior to intervention start date.
Trial locations and contacts
1 site in 1 country.
United States1 site
University of Colorado Anschutz Health and Wellness Center
Aurora, Colorado, 80045
About this study
Official title: Effects of Early vs. Late Time Restricted Eating vs. Daily Caloric Restriction on Weight Loss and Metabolic Outcomes in Adults With Obesity
The goal of this clinical trial is to learn about time restricted eating as a weight loss intervention in adults with obesity. The main questions it aims to answer are:
- How does the timing of the eating window (early vs late time restricted eating) affect weight loss and changes in metabolic risk factors?
- How does time restricted eating compare to standard of care (daily caloric restriction) for weight loss and changes in metabolic risk factors?
Read more
Participants will be randomly assigned to either early time restricted eating, late time restricted eating, or daily caloric restriction.
- They will be asked to follow the assigned dietary strategy for 1 year and will receive a group-based program for instruction and support.
- They will be asked at several times during the year to have their weight and body composition measured, provide blood samples, track their food, and wear monitors for physical activity and sleep.
Read the detailed description
This is a 52-week randomized, parallel-arm clinical trial designed to assess the effects of early time restricted eating (E-TRE) vs late TRE (L-TRE) vs daily caloric restriction (DCR) within the context of a guidelines-based behavioral weight loss program. 162 adults (age 18-65) with obesity (BMI 27-45 kg/m2) will be recruited from the community and randomized 1:1:1 to E-TRE (eating within an 8-hour window starting 1-2 hours after waking), L-TRE (eating within an 8-hour window starting 5-6 hours after waking) or DCR (caloric restriction of 25% from baseline energy requirements). The primary outcome is change in body weight at 26 weeks. Secondary outcomes include body composition, insulin sensitivity, blood pressure, glucose variability, physical activity, and sleep.
- Conditions
- Overweight and Obesity
- Being tested
- Early TRE, Late TRE, DCR
- Medical subject headings
- Overweight, Obesity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Early TREBehavioural
Participants will be instructed to eat only during an 8-hour window starting 1-2 hours after waking.
Late TREBehavioural
Participants will be instructed to eat only during an 8-hour window starting 5-6 hours after waking.
DCRBehavioural
Participants will be instructed to reduce caloric intake by 25%.
| Study group | Role | What they receive |
|---|---|---|
| Early time restricted eating | Experimental | Participants will asked to follow early time restricted eating Receives: Behavioral: Early TRE |
| Late time restricted eating | Experimental | Participants will be asked to follow late time restricted eating Receives: Behavioral: Late TRE |
| Daily caloric restriction | Active comparator | Participants will be instructed to follow daily caloric restriction Receives: Behavioral: DCR |
What is being measured
The primary outcome is the main question the study is designed to answer.
Body weight (kg)
Body weight will be measured using a digital scale at baseline, weeks 14, 26 and 52. The primary outcome will be change in weight from baseline to 26 weeks.
Measured: 0 to 52 weeks
Secondary outcomes (12)
Fat mass
Fat mass will assessed using Dual-Energy X-Ray Absorptiometry (DXA) at baseline, weeks 14, 26 and 52
Measured: 0 to 52 weeks
Lean mass
Lean mass will assessed using Dual-Energy X-Ray Absorptiometry (DXA) at baseline, weeks 14, 26 and 52
Measured: 0-52 weeks
Blood pressure
Systolic and diastolic blood pressure will be measured at baseline and weeks 14, 26 and 52
Measured: 0-52 weeks
HbA1c
HbA1c will be measured at baseline and weeks 14, 26 and 52
Measured: 0-52 weeks
Insulin sensitivity
Insulin sensitivity measured with oral glucose tolerance test at baseline and weeks 14, 26 and 52
Measured: 0-52 weeks
24-hour glucose levels
24-hr glucose levels measured with continuous glucose monitor at baseline and weeks 14, 26 and 52
Measured: 0-52 weeks
Physical activity
Total steps measured with activPal device at baseline and weeks 14, 26 and 52
Measured: 0-52 weeks
Total cholesterol concentration
Total cholesterol concentration will be measured at baseline and weeks 14, 26 and 52
Measured: 0-52 weeks
Sleep duration
Sleep duration (minutes) will be measured with activPal device at baseline and weeks 0, 14 and 26
Measured: 0-52 weeks
LDL cholesterol concentration
Low density lipoprotein (LDL) will be measured at baseline and weeks 14, 26 and 52
Measured: 0-52 weeks
HDL cholesterol concentration
High density lipoprotein (HDL) cholesterol concentration will be measured at baseline and weeks 14, 26 and 52
Measured: 0-52 weeks
Triglyceride concentration
Triglyceride concentration will be measured at baseline and weeks 14, 26 and 52
Measured: 0-52 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 May 2023
- Study start11 Jul 2023
- Primary completionMar 2027 (estimated)
- Study completionSep 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Overweight and ObesityStudies of the same condition, open and under way.
- More trials run by University of Colorado, DenverThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- randomized, parallel-arm clinical trial
- Masking
- Single blind
- Who is masked
- Investigator
- Enrolment
- 162 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Colorado, Denver
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05870982
- Sponsor's protocol ID
- 22-1829
- Other IDs
- R01DK132372
- Acronym
- Time2Eat
- Status last verified
- Mar 2026
- First submitted
- 4 May 2023
- Last updated
- 24 Mar 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 24 Mar 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Effects of Early vs. Late Time Restricted Eating vs. Daily Caloric Restriction on Weight Loss and Metabolic Outcomes in Adults With Obesity
- ClinicalTrials.gov ID
- NCT05870982
- Acronym / sponsor ID
- Time2Eat / 22-1829
- Conditions
- Overweight and Obesity
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 162 participants (estimated)
- Lead sponsor
- University of Colorado, DenverUniversity, hospital or other
- Collaborators
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
- Study start
- 11 Jul 2023 (actual)
- Primary completion
- Mar 2027 (estimated)
- Study completion
- Sep 2027 (estimated)
- First posted
- 23 May 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this clinical trial is to learn about time restricted eating as a weight loss intervention in adults with obesity. The main questions it aims to answer are:
- How does the timing of the eating window (early vs late time restricted eating) affect weight loss and changes in metabolic risk factors?
- How does time restricted eating compare to standard of care (daily caloric restriction) for weight loss and changes in metabolic risk factors?
Participants will be randomly assigned to either early time restricted eating, late time restricted eating, or daily caloric restriction.
- They will be asked to follow the assigned dietary strategy for 1 year and will receive a group-based program for instruction and support.
- They will be asked at several times during the year to have their weight and body composition measured, provide blood samples, track their food, and wear monitors for physical activity and sleep.
Detailed description
This is a 52-week randomized, parallel-arm clinical trial designed to assess the effects of early time restricted eating (E-TRE) vs late TRE (L-TRE) vs daily caloric restriction (DCR) within the context of a guidelines-based behavioral weight loss program. 162 adults (age 18-65) with obesity (BMI 27-45 kg/m2) will be recruited from the community and randomized 1:1:1 to E-TRE (eating within an 8-hour window starting 1-2 hours after waking), L-TRE (eating within an 8-hour window starting 5-6 hours after waking) or DCR (caloric restriction of 25% from baseline energy requirements). The primary outcome is change in body weight at 26 weeks. Secondary outcomes include body composition, insulin sensitivity, blood pressure, glucose variability, physical activity, and sleep.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (investigator)
- Number of arms
- 3
- Model description
- randomized, parallel-arm clinical trial
| Arm | Type | Receives |
|---|---|---|
| Early time restricted eating | Experimental | Behavioral: Early TREParticipants will asked to follow early time restricted eating |
| Late time restricted eating | Experimental | Behavioral: Late TREParticipants will be asked to follow late time restricted eating |
| Daily caloric restriction | Active comparator | Behavioral: DCRParticipants will be instructed to follow daily caloric restriction |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (9 listed)
- Adult males and females with a BMI of 27-45 kg/m2
- Age, 18-65 years old
- Passing medical and physical screening, and analysis of blood and urine screening samples
- Individuals who are not currently following an intermittent fasting or TRE dietary regimen (i.e., eating across less than a 10-hour period during the day).
- Own a smartphone
Key exclusion criteria (24 listed)
- Pregnancy or lactation for women (women who are >6 months postpartum with no plans of becoming pregnant in the next year and who are not currently lactating can be included; oral contraceptives will be allowed if medication has been consistent for the prior 6 months)
- Weight loss >5kg in past 3 months for any reason except post-partum weight loss, weight gain >5kg in past 3 months requires assessment by PI to determine reason for weight gain and if it is appropriate for the subject to participate in the study
- Weight loss of >50 lbs in past 3 years for any reason except post-partum weight loss
- Presence or history of any metabolic or chronic health problems which would affect appetite, food intake, energy metabolism, or ability to optimally participate in the exercise component including: CVD, peripheral vascular disease, cerebrovascular disease, significant cardiac arrhythmias or cardiac valve disease, diabetes, uncontrolled hyper- or hypothyroidism, uncontrolled hypertension, cancer (within the last 5 years, except skin cancer or other cancers considered cured with excellent prognosis), HIV infection, seizure disorders, significant gastrointestinal disorders (described below), significant pulmonary disorders (described below), significant renal, musculoskeletal, neurologic, hematologic, or psychiatric disease.
- Significant gastrointestinal disorders including: chronic malabsorptive conditions, peptic ulcer disease, Crohn's disease, Ulcerative Colitis, chronic diarrhea, or active gallbladder disease.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Early TREParticipants will be instructed to eat only during an 8-hour window starting 1-2 hours after waking. | Behavioural | Early time restricted eating |
| Late TREParticipants will be instructed to eat only during an 8-hour window starting 5-6 hours after waking. | Behavioural | Late time restricted eating |
| DCRParticipants will be instructed to reduce caloric intake by 25%. | Behavioural | Daily caloric restriction |
Primary outcome
Body weight (kg)
Time frame: 0 to 52 weeks
Body weight will be measured using a digital scale at baseline, weeks 14, 26 and 52. The primary outcome will be change in weight from baseline to 26 weeks.
12 secondary outcomes
Fat mass
Time frame: 0 to 52 weeks
Lean mass
Time frame: 0-52 weeks
Blood pressure
Time frame: 0-52 weeks
HbA1c
Time frame: 0-52 weeks
Insulin sensitivity
Time frame: 0-52 weeks
24-hour glucose levels
Time frame: 0-52 weeks
Physical activity
Time frame: 0-52 weeks
Total cholesterol concentration
Time frame: 0-52 weeks
Sleep duration
Time frame: 0-52 weeks
LDL cholesterol concentration
Time frame: 0-52 weeks
HDL cholesterol concentration
Time frame: 0-52 weeks
Triglyceride concentration
Time frame: 0-52 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 24 Mar 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Early TRE, Late TRE and DCR in people with Overweight and Obesity, run by University of Colorado, Denver at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 9 inclusion and 24 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: under way, not looking for participants, as of the sponsor's last update on 24 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Body weight (kg) (time frame: 0 to 52 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 24 Mar 2026.