ObesityNCT04259632
Prolonged Daily Fasting as a Viable Alternative to Caloric Restriction in At-Risk Obese Humans
A study testing Time Restricted Eating (TRE) and Caloric Restriction (CR) in people with Obesity, run by University of Minnesota at 1 site in United States.
Trial summary
Purpose: Obesity is reaching epidemic proportions, affecting 36% of the adult population in the United States. There is intense interest in dietary management to treat obesity and its associated complications. The first line of obesity treatment is caloric restriction (CR), although recidivism is common. Read more about this study
- Who is it for?
- Ages 18 to 65 years
- Conditions the study is for
- Obesity
- What is being tested?
- Time Restricted Eating (TRE) and Caloric Restriction (CR)
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 115 participants
- Where
- 1 siteUnited States
- Study dates
- 15 Oct 2020to 31 Dec 2025
- Phase
- Interventional
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
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
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- BMI ≥30 and ≤ 55 kg/m^2
- Own a smartphone compatible with the myCircadianClock (mCC) phone application
- Self-reported habitual wakening between 5-9 am
- Self reported sleep duration of 6-9 hours
- Weight must be stable [+/- 5 pounds] for at least 3 months prior to the study
- Eating window (time between 1st food intake and last food take) ≥14 hours using mCC
- Insulin resistance based on HOMA-IR≥ 2.5 from screening visit results
- Able to understand English
Who cannot join
- Use of beta-blockers or medications known to affect weight, such as thiazolidinedione (TZD), insulin, glucagon-like peptide (GLP)-1 agonists, phentermine, or sibutamine
- Shift work (i.e. working from 11pm to 7am)
- Clinically significant medical issues (diabetes, cardiovascular disease, uncontrolled pulmonary disease)
- A history of abnormal laboratory results, such as hematologic (platelets < 100), hepatic (LFTs > 2X nl), renal (Cr > 1.5)
- MRI contraindication (metal in body, claustrophobia)
- Eating window < 12 hours per day
Show all 11Show fewer
- Unable to consistently document food intake using the mCC app (need at least 2 eating occasions> 6 hours apart on a given day for at least 50% of days)
- Pregnancy
- Illiteracy
- Concern for active eating disorder per screening questionnaire
- Self-reported eating disorder or history of eating disorder
Trial locations and contacts
1 site in 1 country.
United States1 site
University of Minnesota
Minneapolis, Minnesota, 55455
About this study
Purpose: Obesity is reaching epidemic proportions, affecting 36% of the adult population in the United States. There is intense interest in dietary management to treat obesity and its associated complications. The first line of obesity treatment is caloric restriction (CR), although recidivism is common. For moderate CR, attrition rates of 20% are often reported, therefore weight loss options beyond CR are urgently needed.
Read the detailed description
Aim#1: Evaluate the effect of TRE with ad libitum intake on weight and body composition.
H 1.1: Individuals in the TRE and CR groups will have similar weight loss, which will be greater than weight loss achieved in the non-TRE group (primary outcome).
H 1.2: TRE will result in greater loss of loss of total body fat (quantified by DXA) and greater loss of hepatic/visceral fat/ectopic fat (quantified by MRI) than CR.
Aim#2: Assess the effect of TRE with ad libitum intake on caloric balance. H 2.1: TRE will reduce caloric intake compared with non-TRE [gold-standard interviewer administered 24-hour dietary recall (primary outcome)] with similar reduction as with CR, H.2.2: Compared with non-TRE, TRE will result in selection of more nutrient dense foods during a supervised meal within their eating window; this selection will be similar to CR. H 2.3 TRE will not alter physical activity, but will increase fat oxidation compared with CR and non-TRE.
Aim#3: Assess the effect of TRE with ad libitum intake on metabolic flexibility.
H 3.1: TRE will enhance metabolic flexibility compared with CR and non-TRE as measured by indirect calorimetry [RQ:Respiratory quotient before and during 2 step 6,6-2H2 hyperinsulinemic-euglycemic clamp: primary outcome].
H 3.2: TRE will improve insulin sensitivity compared with non-TRE and similar to CR.
H 3.3: TRE will augment greater fasting lipolysis compared to CR and non-TRE as measured by [U-13C] palmitate and enhance lipolysis suppression during the 2 step 6,6-2H2 hyperinsulinemic-euglycemic clamp.
If these hypotheses are confirmed, this project has significant impact. First, it will advance understanding of the mechanisms underpinning this innovative intervention. Second, TRE can be a practical means of implementing prolonged fasting on a large scale, thereby transforming the treatment of obesity.
Research reported in this publication was supported by the National Center for Advancing Translational Sciences of the National Institutes of Health Award Number UL1-TR002494. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
- Conditions
- Obesity
- Being tested
- Time Restricted Eating (TRE), Caloric Restriction (CR)
- Medical subject headings
- Obesity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Time Restricted Eating (TRE)Behavioural
daily eating window restricted to 8 hours
Caloric Restriction (CR)Behavioural
15% daily caloric deficient
| Study group | Role | What they receive |
|---|---|---|
| Time Restricted Eating (TRE) | Experimental | For the TRE group, we will restrict the eating window to 8 hours, where they will eat ad libitum. This is the same interval established by Dr. Panda and by our preliminary data. This interval will be entered into the mCC app and participants will be asked to adhere to this eating window during the intervention. All eating occasions will be logged using the mCC app. Only water and medications will be allowed outside of the eating window. Receives: Behavioral: Time Restricted Eating (TRE) |
| Caloric Restriction (CR) | Active comparator | Participants randomized to CR will meet with the study dietitian prior to the intervention and be counseled on options to reduce their caloric intake by 15%, while maintaining their eating window. The 15% reduction was selected as our preliminary data and recent literature suggest that TRE with ad libitum intake reduces caloric intake by ~270 to 300 cal/day. The 15% CR is similar to the 11.9% CR achieved by the CALERIE-2 study, which is a 2 year study of CR.26 All eating occasions will be logged using the mCC app. The weekly dietitian review of the mCC information will include maintenance of the eating window and examination of dietary intake to determine compliance with the 15% CR. Receives: Behavioral: Caloric Restriction (CR) |
| Unrestricted Eating (non-TRE) | No intervention | For the unrestricted eating (non-TRE) group, participants will eat ad libitum per their usual habits. They will receive initial counseling about mCC logging. All eating occasions will be logged using the mCC app. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in Weight
Weight will be measured by standard scale and reported in kilograms. This between 2 time points - baseline and 12 weeks
Measured: 12 weeks
Secondary outcomes (6)
Change in Whole Body Percent Fat
Body composition will be measured by dual energy x-ray absorptometry (DXA). Parameters of body composition will be calculated by integrated DXA software. Whole body percent fat will be reported as a percentage.
Measured: Baseline, 12 weeks
Change in Visceral Fat
Body composition will be measured by dual energy x-ray absorptometry (DXA). Parameters of body composition will be calculated by integrated DXA software. Visceral fat will be reported in grams.
Measured: Baseline, 12 weeks
Change in Lean Mass
Body composition will be measured by dual energy x-ray absorptometry (DXA). Parameters of body composition will be calculated by integrated DXA software. Lean mass will be reported in kilograms.
Measured: Baseline, 12 weeks
Change in Fat Mass
Body composition will be measured by dual energy x-ray absorptometry (DXA). Parameters of body composition will be calculated by integrated DXA software. Fat mass will be reported in kilograms.
Measured: Baseline, 12 weeks
Change in Caloric Intake
Two interviewer-administered 24-hour dietary recalls will be collected from each participant at baseline and 12 weeks. The recalls will be conducted over the telephone and will be unannounced to minimize measurement reactivity. Diet data will be collected using the Nutrition Data System for Research (NDSR) to calculate Calories. Calories will be averaged across the 2 recalls at each time point. Outcome will be reported as difference between average caloric intake at baseline and 12 weeks. Outcome will be reported in kilocalories (Calories).
Measured: Baseline, 12 weeks
Change in Metabolic Flexibility
indirect calorimetry to measure glucose and fat oxidation for ~ 30 minutes before and at the end of the 2 step 4-hour hyperinsulinemic-euglycemic clamp [low-dose (10 mU/m2/min) insulin infusion for 2 hours, high-dose (40 mU/m2/min) insulin infusion for 2 hours] Fluctuations in VO2 and VCO2 in the first 5-10 minutes of data acquisition were removed and the mean VO2 and VCO2 at steady state was used for data analysis. The respiratory exchange ratio (RER) was calculated by VCO2 / VO2. . Metabolic flexibility was calculated by the RERclamp-RERrest
Measured: baseline, 12 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 Feb 2020
- Study start15 Oct 2020
- Primary completion12 Oct 2023
- Study completion31 Dec 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for ObesityStudies of the same condition, open and under way.
- More trials run by University of MinnesotaThe 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
- Masking
- Single blind
- Who is masked
- Outcomes assessor
- Enrolment
- 115 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Minnesota
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04259632
- Sponsor's protocol ID
- MED-2019-28331
- Other IDs
- R01DK124484
- Status last verified
- Jan 2026
- First submitted
- 4 Feb 2020
- Last updated
- 23 Jan 2026
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Publications
Chen DA, Pena RH, Oldenburg N, Wang Q, Helgeson E, Yentzer B, Taddese A, LaPage N, Manoogian ENC, Panda S, Chow LS. Post-intervention sustainability of time-restricted eating versus caloric restriction: a secondary analysis. Int J Obes (Lond). 2026 Feb;50(2):474-477. doi: 10.1038/s41366-025-01968-2. Epub 2025 Nov 28.
PubMed 41315749
Study at a glance
From the registry record, last updated by the sponsor on 23 Jan 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Prolonged Daily Fasting as a Viable Alternative to Caloric Restriction in At-Risk Obese Humans
- ClinicalTrials.gov ID
- NCT04259632
- Acronym / sponsor ID
- MED-2019-28331
- Conditions
- Obesity
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 115 participants (actual)
- Lead sponsor
- University of MinnesotaUniversity, hospital or other
- Collaborators
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
- Study start
- 15 Oct 2020 (actual)
- Primary completion
- 12 Oct 2023 (actual)
- Study completion
- 31 Dec 2025 (actual)
- First posted
- 6 Feb 2020 (actual)
- Results
- Posted 24 Feb 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Purpose: Obesity is reaching epidemic proportions, affecting 36% of the adult population in the United States. There is intense interest in dietary management to treat obesity and its associated complications. The first line of obesity treatment is caloric restriction (CR), although recidivism is common. For moderate CR, attrition rates of 20% are often reported, therefore weight loss options beyond CR are urgently needed.
Detailed description
Aim#1: Evaluate the effect of TRE with ad libitum intake on weight and body composition.
H 1.1: Individuals in the TRE and CR groups will have similar weight loss, which will be greater than weight loss achieved in the non-TRE group (primary outcome).
H 1.2: TRE will result in greater loss of loss of total body fat (quantified by DXA) and greater loss of hepatic/visceral fat/ectopic fat (quantified by MRI) than CR.
Aim#2: Assess the effect of TRE with ad libitum intake on caloric balance. H 2.1: TRE will reduce caloric intake compared with non-TRE [gold-standard interviewer administered 24-hour dietary recall (primary outcome)] with similar reduction as with CR, H.2.2: Compared with non-TRE, TRE will result in selection of more nutrient dense foods during a supervised meal within their eating window; this selection will be similar to CR. H 2.3 TRE will not alter physical activity, but will increase fat oxidation compared with CR and non-TRE.
Aim#3: Assess the effect of TRE with ad libitum intake on metabolic flexibility.
H 3.1: TRE will enhance metabolic flexibility compared with CR and non-TRE as measured by indirect calorimetry [RQ:Respiratory quotient before and during 2 step 6,6-2H2 hyperinsulinemic-euglycemic clamp: primary outcome].
H 3.2: TRE will improve insulin sensitivity compared with non-TRE and similar to CR.
H 3.3: TRE will augment greater fasting lipolysis compared to CR and non-TRE as measured by [U-13C] palmitate and enhance lipolysis suppression during the 2 step 6,6-2H2 hyperinsulinemic-euglycemic clamp.
If these hypotheses are confirmed, this project has significant impact. First, it will advance understanding of the mechanisms underpinning this innovative intervention. Second, TRE can be a practical means of implementing prolonged fasting on a large scale, thereby transforming the treatment of obesity.
Research reported in this publication was supported by the National Center for Advancing Translational Sciences of the National Institutes of Health Award Number UL1-TR002494. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind (outcomes assessor)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| Time Restricted Eating (TRE) | Experimental | Behavioral: Time Restricted Eating (TRE)For the TRE group, we will restrict the eating window to 8 hours, where they will eat ad libitum. This is the same interval established by Dr. Panda and by our preliminary data. This interval will be entered into the mCC app and participants will be asked to adhere to this eating window during the intervention. All eating occasions will be logged using the mCC app. Only water and medications will be allowed outside of the eating window. |
| Caloric Restriction (CR) | Active comparator | Behavioral: Caloric Restriction (CR)Participants randomized to CR will meet with the study dietitian prior to the intervention and be counseled on options to reduce their caloric intake by 15%, while maintaining their eating window. The 15% reduction was selected as our preliminary data and recent literature suggest that TRE with ad libitum intake reduces caloric intake by ~270 to 300 cal/day. The 15% CR is similar to the 11.9% CR achieved by the CALERIE-2 study, which is a 2 year study of CR.26 All eating occasions will be logged using the mCC app. The weekly dietitian review of the mCC information will include maintenance of the eating window and examination of dietary intake to determine compliance with the 15% CR. |
| Unrestricted Eating (non-TRE) | No intervention | –For the unrestricted eating (non-TRE) group, participants will eat ad libitum per their usual habits. They will receive initial counseling about mCC logging. All eating occasions will be logged using the mCC app. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (8 listed)
- BMI ≥30 and ≤ 55 kg/m^2
- Own a smartphone compatible with the myCircadianClock (mCC) phone application
- Self-reported habitual wakening between 5-9 am
- Self reported sleep duration of 6-9 hours
- Weight must be stable [+/- 5 pounds] for at least 3 months prior to the study
Key exclusion criteria (11 listed)
- Use of beta-blockers or medications known to affect weight, such as thiazolidinedione (TZD), insulin, glucagon-like peptide (GLP)-1 agonists, phentermine, or sibutamine
- Shift work (i.e. working from 11pm to 7am)
- Clinically significant medical issues (diabetes, cardiovascular disease, uncontrolled pulmonary disease)
- A history of abnormal laboratory results, such as hematologic (platelets < 100), hepatic (LFTs > 2X nl), renal (Cr > 1.5)
- MRI contraindication (metal in body, claustrophobia)
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 |
|---|---|---|
| Time Restricted Eating (TRE)daily eating window restricted to 8 hours | Behavioural | Time Restricted Eating (TRE) |
| Caloric Restriction (CR)15% daily caloric deficient | Behavioural | Caloric Restriction (CR) |
Primary outcome
Change in Weight
Time frame: 12 weeks
Weight will be measured by standard scale and reported in kilograms. This between 2 time points - baseline and 12 weeks
6 secondary outcomes
Change in Whole Body Percent Fat
Time frame: Baseline, 12 weeks
Change in Visceral Fat
Time frame: Baseline, 12 weeks
Change in Lean Mass
Time frame: Baseline, 12 weeks
Change in Fat Mass
Time frame: Baseline, 12 weeks
Change in Caloric Intake
Time frame: Baseline, 12 weeks
Change in Metabolic Flexibility
Time frame: baseline, 12 weeks
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 23 Jan 2026.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Derived from this study: PubMed 41315749Chen DA, Pena RH, Oldenburg N, Wang Q, Helgeson E, Yentzer B, Taddese A, LaPage N, Manoogian ENC, Panda S, Chow LS. Post-intervention sustainability of time-restricted eating versus caloric restriction: a secondary analysis. Int J Obes (Lond). 2026 Feb;50(2):474-477. doi: 10.1038/s41366-025-01968-2. Epub 2025 Nov 28.
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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 Time Restricted Eating (TRE) and Caloric Restriction (CR) in people with Obesity, run by University of Minnesota 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 8 inclusion and 11 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: finished, as of the sponsor's last update on 23 Jan 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?
Yes. Results are posted in the registry (first posted 24 Feb 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
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?
Change in Weight (time frame: 12 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT04259632, which also lists 1 linked publication.
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 23 Jan 2026.