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ObesityPhase 2NCT07487090

Fasted vs. Fed State Exercise

A Phase 2 study testing 16 week exercise intervention in people with Obesity and Exercise, run by Arkansas Colleges of Health Education at 1 site in United States.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
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Trial summary

Although many medications exist for both heart disease and obesity, cost, lack of access for all people, side effects and the desire for a more natural solution have left many people seeking lifestyle treatments such as exercise. Scientists know that exercise is highly beneficial for heart health. Read more about this study

Who is it for?
Ages 18 to 59 yearsHealthy volunteers can take part
Conditions the study is for
Obesity, Exercise, Weight Loss
What is being tested?
16 week exercise intervention
Could I receive a placebo?
No, everyone receives an active treatment
How many people
40 participants
Where
1 siteUnited States
Study dates
5 Jan 2026to Dec 2027
Phase
Phase 2
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 59 years
  • All sexes
  • Healthy volunteers accepted
  • Adult

Who may be able to join

  • Aged 18-59
  • BMI 25-45
  • Healthy enough to exercise

Who cannot join

  • Taking medications or supplements that are known to influence energy expenditure,
  • Currently exercising more than once per week
  • Currently dieting for weight loss
  • Currently taking weight loss drugs
  • Have had a previous weight loss surgery
  • Currently diagnosed with Diabetes
  • Currently diagnosed with heart disease (Heart failure, uncontrolled hypertension, uncontrolled hypercholesterolemia, Coronary heart disease)

Trial locations and contacts

1 site in 1 country. Contact the study team or a site near you to ask about taking part.

Kyle D Flack, PhD contact

(479) 434-4019

kyle.flack@achehealth.edu

Blake Metcalf, DCN contact

479-434-4003

blake.metcalf@achehealth.edu

United States1 site, 1 recruiting

  • Arkansas Colleges of Health Education Research Institure Health and Wellness Center

    Fort Smith, Arkansas, 72916

    Kyle D Flack, PhD, (479) 434-4019, kyle.flack@achehealth.edu

    Blake Metcalf, DCN, 4794344003, blake.metcalf@achehealth.edu

    Recruiting

Other trials in United States

About this study

Official title: Fasted vs. Fed State Exercise for Cardiovascular Health and Weight Loss

Although many medications exist for both heart disease and obesity, cost, lack of access for all people, side effects and the desire for a more natural solution have left many people seeking lifestyle treatments such as exercise. Scientists know that exercise is highly beneficial for heart health. When exercise also produces weight loss, these benefits are much improved. Although using exercise to treat or prevent heart disease / obesity is recommended, not all people respond well. Some see significant weight loss and health improvements while others see little changes. For these reasons, new strategies surrounding the use and design of an exercise program are needed. One such strategy could be performing aerobic exercise before breakfast (fasted exercise). When exercising fasted, food/energy stores are low, and one relies on stored body fat for energy. This may help heart health and weight loss. This has never been tested in a program long enough to see such changes. This study will, for the first time, assess the effects of a 16-week aerobic exercise program performed fasted compared to after eating. Outcomes will include blood fats, blood pressure, fat-burning abilities and weight loss.

Starting an exercise program can also make people to eat more. This limits the success of exercise. The study will also evaluate ways fasted exercise could change eating, as it possible that fasted exercise could also cause people to eat more, which would limit weight loss and health improvements.

Read the detailed description

This study will be the first to evaluate a long-term (16-week) aerobic exercise intervention performed in the fasted state (compared to fed state) at a guidelines-based dose. Primary outcomes for Aim 1 will include changes in fat \& fat-free mass (DXA), energy compensation, blood pressure \& lipids, aerobic fitness, and substrate oxidation (respiratory quotient, RQ) at rest and during activity.

It is also important to understand sources of response variability to an exercise program. Individuals tend to compensate for the energy they expend during exercise, primarily by increasing energy intake (EI). Such compensatory eating behaviors likely stem from a series of evolutionarily conserved responses, ensuring energy is available for vital organ function and reproduction when faced with an energy deficit. This proposal will be the first to evaluate how fasted exercise training influences (Aim 2 outcomes): physiological hunger (hormonal responses to a standardized meal) and behavioral constructs shown to influence EI and weight status (food reinforcement and attentional bias towards food cues). The overall hypothesis is that fasted state exercise will result in greater energy compensation, attenuating weight loss compared to an identical dose of exercise performed in the post-prandial state. This study will further hypothesize an attenuated weight loss with fasted exercise training will negate beneficial cardiovascular adaptations stemming from improvements in oxidative metabolism commonly associated with fasted exercise. Adults (aged 18-59 years, BMI: 25-45 kg/m2) will be randomized to a 16-week supervised aerobic exercise intervention (progressing to a guidelines-based dose of 1600 kcal/wk). Exercise sessions will be performed between 0500h and 1100h, 4 days per week in either the fasted state (FAST, 8-12 hour fast) or post-prandially (FED, within 3 hours of eating at least 300 kcal).

Being tested
16 week exercise intervention
Keywords
Exercise, weight loss, obesity
Medical subject headings
Obesity, Motor Activity, Weight Loss

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • 16 week exercise interventionBehavioural

    Both groups will receive a 16-week supervised aerobic exercise program progressing to 1,600 kcal of EE per wk (4 sessions/week) at moderate intensity (40-50% heart rate reserve, HRR).

Study groups in NCT07487090
Study groupRoleWhat they receive
Fasted groupExperimentalComplete all exercise sessions of intervention before breakfast- fasted at least 8 hours
Receives: Behavioral: 16 week exercise intervention
Fed exercise groupExperimentalComplete all exercise sessions of intervention after breakfast- within 3 hours of eating at least 300 kcal
Receives: Behavioral: 16 week exercise intervention

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. body composition

    kg of fat free and fat mass via DXA

    Measured: Baseline (week 0) and post-intervention (week 25)

Secondary outcomes (12)

  1. Total and acylated ghrelin

    Total and acylated ghrelin (pg/mL in plasma) will be assessed in the fasted state and response to a test meal via blood sampling at 0 minutes (pre meal), 15, 30, 45, 60, 90, and 120 minutes post-meal.

    Measured: Baseline (week 0) and post-intervention (week 25)

  2. GLP-1

    Glucagon-like peptide 1 (GLP-1, Pmol/L in plasma) will be assessed in the fasted state and response to a test meal via blood sampling at 0 minutes (pre meal), 15, 30, 45, 60, 90, and 120 minutes post-meal.

    Measured: Baseline (week 0) and post-intervention (week 25)

  3. PYY

    Peptide YY (PYY, pmol/L plasma) will be assessed in the fasted state and response to a test meal via blood sampling at 0 minutes (pre meal), 15, 30, 45, 60, 90, and 120 minutes post-meal.

    Measured: Baseline (week 0) and post-intervention (week 25)

  4. Leptin

    Leptin (ng/mL in plasma) will be assessed in the fasted state and response to a test meal via blood sampling at 0 minutes (pre meal), 15, 30, 45, 60, 90, and 120 minutes post-meal.

    Measured: Baseline (week 0) and post-intervention (week 25)

  5. Food reinforcement

    amount of work one is willing to do for a snack food

    Measured: Baseline (week 0) and post-intervention (week 25)

  6. Attentional bias for food cues

    percentage of time fixated on food cues during a dot-probe task, assessed by eye tracking

    Measured: Baseline (week 0) and post-intervention (week 25)

  7. Skeletal muscle efficiency

    kcal expended per kg per watt during a graded cycle ergometer test

    Measured: Baseline (week 0) and post-intervention (week 25)

  8. walking ecconomy

    Gross energetic cost of movement (J/kg/m) will be assessed during a graded walking test with indirect calorimetry.

    Measured: Baseline (week 0) and post-intervention (week 25)

  9. resting metabolic rate

    Resting metabolic rate assessed via indirect calorimetry

    Measured: Baseline (week 0) and post-intervention (week 25)

  10. muscle strength

    Peak torque and work per repetition (Foot-Pounds) will be assessed during an isokinetic and isometric task

    Measured: Baseline (week 0) and post-intervention (week 25)

  11. muscle power

    Average power (watts) will be assessed during an isokinetic and isometric task

    Measured: Baseline (week 0) and post-intervention (week 25)

  12. skeletal muscle mass

    The D3Cr dilution technique will be used to determine kg of skeletal muscle mass

    Measured: Baseline (week 0) and post-intervention (week 25)

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted23 Mar 2026
  2. Study start5 Jan 2026
  3. Primary completionJul 2027 (estimated)
  4. Study completionDec 2027 (estimated)

Resources

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 2
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Model description
2 group trial, 1:1 allocation, Fed exercise group (complete all exercise sessions of the intervention within 3 hrs of eating) vs. Fasted exercise group (complete all exercise sessions of the intervention in fasted state)
Masking
None (open label)
Enrolment
40 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT07487090
Sponsor's protocol ID
479-401-6011
Status last verified
Mar 2026
First submitted
13 Mar 2026
Last updated
23 Mar 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
Undecided

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing 16 week exercise intervention in people with Obesity and Exercise, run by Arkansas Colleges of Health Education 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 3 inclusion and 7 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: looking for participants now, as of the sponsor's last update on 23 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.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

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?

Contact Kyle D Flack, PhD ((479) 434-4019, kyle.flack@achehealth.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

body composition (time frame: Baseline (week 0) and post-intervention (week 25)). 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 NCT07487090.

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 Mar 2026.

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Fasted vs. Fed State Exercise (NCT07487090) | AzTrials