Overweight and ObesityTANDEMNCT06311487
Time and Nutrient-Dependent Effects of Aerobic Exercise on Metabolism in Adults (TANDEM Study)
A study testing Fasted-AM, Fed-AM and Fasted-PM in people with Overweight and Obesity and Healthy, run by University of Colorado, Denver at 1 site in United States.
Trial summary
This study plans to learn more about metabolic responses to aerobic exercise at different times of the day (morning or evening) under fasting versus fed conditions. Read more about this study
- Who is it for?
- Ages 18 to 40 years
- Conditions the study is for
- Overweight and Obesity, Healthy
- What is being tested?
- Fasted-AM, Fed-AM and Fasted-PM
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 1 siteUnited States
- Study dates
- 15 Apr 2024to 1 Mar 2026
- 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 40 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- Age 18-40 years
- Body Mass Index 18.5-<40 kg/m2
- Recreationally active: defined as >100 minutes per week of voluntary exercise at moderate intensity or greater and >60 min per day of total habitual physical activity (i.e., work related, transportation related) at moderate intensity or greater, over the past 3 months.
- No self-report of acute or chronic disease (cardiovascular disease (CVD), diabetes, pulmonary, gastrointestinal disorders, and orthopedic problems in particular).
- No plans to relocate within the next 6 months.
- No plans for extended travel (>2 weeks) within the next 6 months.
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- Live or work within 30 minutes of the AHWC (exceptions may be made at the discretion of the Study PI on a case-by-case basis for highly motivated subjects).
- Capable and willing to give informed consent, understand exclusion criteria, and adhere to study conditions.
- 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.
- No contraindications to exercise or limitations on ability to be physically active.
- Ability to complete AM or PM exercise and complete 4 exercise sessions per week.
- Ability to adhere to eating and exercise protocols (meal timing, exercising in fasted and fed states)
- Willing and able to wear activity/sleep monitor for 7 consecutive days.
- Willing not to enroll in any other formal weight loss or physical activity programs over the next 6 months.
- For Females:
- Not currently pregnant or lactating.
- Not pregnant within the past 6 months.
- Not planning to become pregnant in the next 6 months
Who cannot join
- Diastolic blood pressure >100 mmHG, systolic blood pressure >160 mmHG, or resting heart rate >100 bpm as measured in duplicate on the screening visit after 5 minutes of rest in a seated position.
- Diabetes (fasting glucose >/=126 mg/dL or Hemoglobin A1C >/=6.5%) as measured during the screening visit.
- Undiagnosed hypo- or hyper-thyroidism (TSH outside of the normal range as measured during the screening visit) or history of uncontrolled thyroid disorder. History of thyroid disease or current thyroid disease treated with a stable medication regimen for at least 6 months is acceptable.
- Hematocrit, white blood cell count or platelets significantly outside the normal reference range as measured on the screening visit.
- Triglycerides >400 mg/dL as measured on the screening visit.
- LDL cholesterol >200 mg/dL as measured on the screening visit.
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- Abnormal resting electrocardiogram (ECG) as measured on the screening visit: serious arrhythmias, including multifocal PVC's, frequent PVC's (defined as 10 or more per min), ventricular tachycardia (defined as runs of 3 or more successive PVC's), or sustained atrial tachyarrhythmia; 2nd or 3rd degree A-V block, QTc interval > 480 msec or other significant conduction defects.
- Presence or history of any metabolic or chronic health problems which would affect appetite, food intake, energy metabolism, or ability to participate in exercise: 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, 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.
- Symptoms suggestive of CVD: chest pain, shortness of breath at rest or with mild exertion, syncope.
- Regular use of prescription or over-the-counter medications known to significantly impact appetite, weight, or energy metabolism (e.g., appetite suppressants, lithium, stimulants, anti-psychotics, tricyclic antidepressants).
- Use of medications that would impact ability to achieve age-predicted maximum heart rate (e.g. beta blockers).
- Regular use of systemic steroids (other than Oral Contraceptive Pills).
- Regular use of obesity pharmacotherapeutic agents within the last 6 months.
- Current alcohol or substance abuse.
- Nicotine use (past 6 months).
- Current severe depression or history of severe depression within the previous year, based on DSM-IV-TR criteria for Major Depressive Episode. Score > 16 on the Center for Epidemiologic Studies Depression Scale (CES-D) will require further assessment by the Study MD to determine if it is appropriate for the subject to participate
- History of other significant psychiatric illness (e.g., psychosis, schizophrenia, mania, bipolar disorder) which in the opinion of the Study MD would interfere with ability to adhere to the exercise conditions.
- Weight loss >5% in past 3 months.
- Currently participating in or planning to participate in any formal weight loss or physical activity programs or clinical trials.
- Primary sleep disorders including but not limited to insomnia, obstructive sleep apnea, periodic limb movements in sleep, restless leg syndrome.
- Night-time shiftwork, rotating work, or other circadian disruptions and disorders (e.g., diagnosed delayed sleep-wake phase disorder).
- Self-reported long (>9.25h) or short sleep (<7h) that would make adhering the exercise conditions difficult.
- Regular use of prescription or over-the-counter medications known to affect sleep (e.g., benzodiazepines, doxepin, zolpidem, trazodone, diphenhydramine HCl, etc.).
- Regular use of melatonin (>/=2 days per week).
- High consumption of caffeine (>500 mg/d) or unwilling to abstain from caffeine consumption during run-in and in-patient protocol.
- Planned travel >1 time zone away 4 weeks prior to study start or at any time during study protocol.
Trial locations and contacts
1 site in 1 country.
United States1 site
University of Colorado Anschutz Medical Campus
Aurora, Colorado, 80045
About this study
Official title: Examining Time and Nutrient Dependent Effects of Aerobic Exercise on Energy Metabolism in Adults With Overweight and Obesity
This study plans to learn more about metabolic responses to aerobic exercise at different times of the day (morning or evening) under fasting versus fed conditions.
Read the detailed description
This study plans to learn more about metabolic responses to aerobic exercise at different times of the day (morning or evening) under fasting versus fed conditions. Specifically, the investigators will explore the effect of fasted and fed AM and PM aerobic exercise on exercise energy expenditure and substrate oxidation, explore the effect of fasted and fed AM and PM aerobic exercise on plasma metabolites and lipids, and explore the effect of fasted-AM and Fasted-PM on 24h energy expenditure, 24h substrate metabolism, 24h glucose, and 24h profiles of hormonal regulators of energy metabolism
- Conditions
- Overweight and Obesity, Healthy
- Being tested
- Fasted-AM, Fed-AM, Fasted-PM, Fed-PM
- Medical subject headings
- Overweight, Obesity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Fasted-AMBehavioural
Participants will engage in aerobic exercise within 4 hours of waking up, following a >10h overnight fast across the 4d run-in and exercise metabolism assessment day. Energy and macronutrient-controlled meals will be consumed at ~08:00, ~13:00, and ~19:00. Plasma metabolite samples will be drawn immediately pre- and post- exercise.
Fed-AMBehavioural
Participants will engage in exercise within 4 hours of waking up, approximately 1h after consuming breakfast across the 4d run-in and exercise metabolism assessment day. Energy and macronutrient-controlled meals will be consumed at ~07:00, ~12:00, and ~18:00. Plasma metabolite samples will be drawn immediately pre- and post-exercise.
Fasted-PMBehavioural
Participants will engage in exercise between 8-12 hours after waking up, following a ~10h fast across the 4d run-in and exercise metabolism assessment day. Energy and macronutrient-controlled meals will be consumed at ~07:00 and ~18:00. Plasma metabolite samples will be drawn immediately pre- and post-exercise.
Fed-PMBehavioural
Participants will engage in exercise between 8-12 hours after waking up, approximately 1h after consuming dinner across the 4d run-in and exercise metabolism assessment day. Energy and macronutrient-controlled meals will be consumed at ~07:00, ~12:00, and ~18:00. Plasma metabolite samples will be drawn immediately pre- and post-exercise.
| Study group | Role | What they receive |
|---|---|---|
| TANDEM Exercise | Experimental | Participants in this arm will engage in morning aerobic exercise while in a fasted state, morning aerobic exercise while in a fed state, evening aerobic exercise while in a fasted state, and evening aerobic exercise while in a fed state in a randomly assigned order Receives: Behavioral: Fasted-AM; Behavioral: Fed-AM; Behavioral: Fasted-PM; Behavioral: Fed-PM |
What is being measured
The primary outcome is the main question the study is designed to answer.
Exercise Energy Expenditure (kcals)
On Day 5 of each condition, participants will complete a 45-minute exercise test on the treadmill to compare exercise energy expenditure and fat oxidation between. O2 and CO2 content of expired air will be measured continuously by open circuit spirometry and averaged every minute using an automated online system (TrueMax 2400; Parvo-Medics, Sandy, UT). Exercise energy expenditure will be determined from minute-by-minute values, measured in kcals.
Measured: Fasted-AM Day 5, Fed-AM Day 5, Fasted-PM Day 5, Fed-PM Day 5
Substrate Oxidation (Respiratory Quotient)
On Day 5 of each condition, participants will complete a 45-minute exercise test on the treadmill to compare exercise energy expenditure and fat oxidation between. O2 and CO2 content of expired air will be measured continuously by open circuit spirometry and averaged every minute using an automated online system (TrueMax 2400; Parvo-Medics, Sandy, UT). Substrate Oxidation will be determined from minute-by-minute values, measured in respiratory quotient.
Measured: Fasted-AM Day 5, Fed-AM Day 5, Fasted-PM Day 5, Fed-PM Day 5
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Mar 2024
- Study start15 Apr 2024
- Primary completion1 Mar 2026 (estimated)
- Study completion1 Mar 2026 (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
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Enrolment
- 20 participants (actual)
Sponsor and investigators
- Lead sponsor
- University of Colorado, Denver
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Seth Creasy, PhD, Principal investigator, University of Colorado, Denver
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06311487
- Sponsor's protocol ID
- 23-1388
- Other IDs
- 1R56DK136601-01
- Acronym
- TANDEM
- Status last verified
- Dec 2025
- First submitted
- 27 Feb 2024
- Last updated
- 19 Dec 2025
- 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 19 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Examining Time and Nutrient Dependent Effects of Aerobic Exercise on Energy Metabolism in Adults With Overweight and Obesity
- ClinicalTrials.gov ID
- NCT06311487
- Acronym / sponsor ID
- TANDEM / 23-1388
- Conditions
- Overweight and Obesity, Healthy
- Study type
- Interventional
- Recruitment status
- Active, not recruiting
- Enrolment
- 20 participants (actual)
- Lead sponsor
- University of Colorado, DenverUniversity, hospital or other
- Collaborators
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
- Study start
- 15 Apr 2024 (actual)
- Primary completion
- 1 Mar 2026 (estimated)
- Study completion
- 1 Mar 2026 (estimated)
- First posted
- 15 Mar 2024 (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.
This study plans to learn more about metabolic responses to aerobic exercise at different times of the day (morning or evening) under fasting versus fed conditions.
Detailed description
This study plans to learn more about metabolic responses to aerobic exercise at different times of the day (morning or evening) under fasting versus fed conditions. Specifically, the investigators will explore the effect of fasted and fed AM and PM aerobic exercise on exercise energy expenditure and substrate oxidation, explore the effect of fasted and fed AM and PM aerobic exercise on plasma metabolites and lipids, and explore the effect of fasted-AM and Fasted-PM on 24h energy expenditure, 24h substrate metabolism, 24h glucose, and 24h profiles of hormonal regulators of energy metabolism
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| TANDEM Exercise | Experimental | Behavioral: Fasted-AM, Behavioral: Fed-AM, Behavioral: Fasted-PM, Behavioral: Fed-PMParticipants in this arm will engage in morning aerobic exercise while in a fasted state, morning aerobic exercise while in a fed state, evening aerobic exercise while in a fasted state, and evening aerobic exercise while in a fed state in a randomly assigned order |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (18 listed)
- Age 18-40 years
- Body Mass Index 18.5-<40 kg/m2
- Recreationally active: defined as >100 minutes per week of voluntary exercise at moderate intensity or greater and >60 min per day of total habitual physical activity (i.e., work related, transportation related) at moderate intensity or greater, over the past 3 months.
- No self-report of acute or chronic disease (cardiovascular disease (CVD), diabetes, pulmonary, gastrointestinal disorders, and orthopedic problems in particular).
- No plans to relocate within the next 6 months.
Key exclusion criteria (28 listed)
- Diastolic blood pressure >100 mmHG, systolic blood pressure >160 mmHG, or resting heart rate >100 bpm as measured in duplicate on the screening visit after 5 minutes of rest in a seated position.
- Diabetes (fasting glucose >/=126 mg/dL or Hemoglobin A1C >/=6.5%) as measured during the screening visit.
- Undiagnosed hypo- or hyper-thyroidism (TSH outside of the normal range as measured during the screening visit) or history of uncontrolled thyroid disorder. History of thyroid disease or current thyroid disease treated with a stable medication regimen for at least 6 months is acceptable.
- Hematocrit, white blood cell count or platelets significantly outside the normal reference range as measured on the screening visit.
- Triglycerides >400 mg/dL as measured on the screening visit.
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 |
|---|---|---|
| Fasted-AMParticipants will engage in aerobic exercise within 4 hours of waking up, following a >10h overnight fast across the 4d run-in and exercise metabolism assessment day. Energy and macronutrient-controlled meals will be consumed at ~08:00, ~13:00, and ~19:00. Plasma metabolite samples will be drawn immediately pre- and post- exercise. | Behavioural | TANDEM Exercise |
| Fed-AMParticipants will engage in exercise within 4 hours of waking up, approximately 1h after consuming breakfast across the 4d run-in and exercise metabolism assessment day. Energy and macronutrient-controlled meals will be consumed at ~07:00, ~12:00, and ~18:00. Plasma metabolite samples will be drawn immediately pre- and post-exercise. | Behavioural | TANDEM Exercise |
| Fasted-PMParticipants will engage in exercise between 8-12 hours after waking up, following a ~10h fast across the 4d run-in and exercise metabolism assessment day. Energy and macronutrient-controlled meals will be consumed at ~07:00 and ~18:00. Plasma metabolite samples will be drawn immediately pre- and post-exercise. | Behavioural | TANDEM Exercise |
| Fed-PMParticipants will engage in exercise between 8-12 hours after waking up, approximately 1h after consuming dinner across the 4d run-in and exercise metabolism assessment day. Energy and macronutrient-controlled meals will be consumed at ~07:00, ~12:00, and ~18:00. Plasma metabolite samples will be drawn immediately pre- and post-exercise. | Behavioural | TANDEM Exercise |
Primary outcome
Exercise Energy Expenditure (kcals)
Time frame: Fasted-AM Day 5, Fed-AM Day 5, Fasted-PM Day 5, Fed-PM Day 5
On Day 5 of each condition, participants will complete a 45-minute exercise test on the treadmill to compare exercise energy expenditure and fat oxidation between. O2 and CO2 content of expired air will be measured continuously by open circuit spirometry and averaged every minute using an automated online system (TrueMax 2400; Parvo-Medics, Sandy, UT). Exercise energy expenditure will be determined from minute-by-minute values, measured in kcals.
Substrate Oxidation (Respiratory Quotient)
Time frame: Fasted-AM Day 5, Fed-AM Day 5, Fasted-PM Day 5, Fed-PM Day 5
On Day 5 of each condition, participants will complete a 45-minute exercise test on the treadmill to compare exercise energy expenditure and fat oxidation between. O2 and CO2 content of expired air will be measured continuously by open circuit spirometry and averaged every minute using an automated online system (TrueMax 2400; Parvo-Medics, Sandy, UT). Substrate Oxidation will be determined from minute-by-minute values, measured in respiratory quotient.
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 19 Dec 2025.
- 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.
Seth Creasy, PhD principal investigator
University of Colorado, Denver
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Fasted-AM, Fed-AM and Fasted-PM in people with Overweight and Obesity and Healthy, 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 18 inclusion and 28 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 19 Dec 2025. 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?
Exercise Energy Expenditure (kcals) (time frame: Fasted-AM Day 5, Fed-AM Day 5, Fasted-PM Day 5, Fed-PM Day 5). The study lists 2 primary outcomes in all. 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 19 Dec 2025.