ObesityDIPNCT06309576
Experimental Approach to Test Predictions of Body Weight Regulation Models
A study testing Fasting-refeeding cycle in people with Obesity and Underweight, run by Pennington Biomedical Research Center at 1 site in United States.
Trial summary
The regulation of human body weight and fatness is not fully understood. Although some models of regulation have been proposed (set point, dual-intervention point, others), no studies have been designed to test their predictions. Read more about this study
- Who is it for?
- Ages 18 to 40 yearsHealthy volunteers can take part
- Conditions the study is for
- Obesity, Underweight
- What is being tested?
- Fasting-refeeding cycle
- Type of treatment
- Lifestyle or therapy programme
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 12 participants
- Where
- 1 siteUnited States
- Study dates
- 17 Jan 2025to 3 Dec 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
- Healthy volunteers accepted
- Adult
Who may be able to join
- Body mass index lower than 20 kg/m2 for the low body weight group, or 30 kg/m2 or greater for the obesity group
- 18-40 years old
- Nulliparous and regular menstrual cycle (25-35 days) during the last six months (in women)
- Normal thyroid function, blood count, and chemistry 15 panel (normal plasma glucose will be considered at <100 mg/dL; normal serum HDL cholesterol at >=50 mg/dL for women and >=40 mg/dL for men; and normal serum triglycerides at <150 mg/dL).
- Self-reported weight stability during the last six months (±3 kg)
- Rate the liking of at least one of the flavored liquid meals (Ensure Plus, Abbot Nutrition) between 5 and 8 on a 9-point Likert scale
- Willing to only drink up to two assigned flavors of Ensure Plus for two consecutive days
Who cannot join
- Eating disorders as indicated by a global score ≥2.80 in the Eating Disorder Examination Questionnaire, or a previous diagnosis of an eating disorder
- For the low body weight group, having food insecurity (with or without hunger) as assessed by the USDA
- Recreational moderate-intensity physical activity ≥150 min/week, recreational vigorous-intensity physical activity ≥75 min/week, or a combination of recreational moderate-intensity and vigorous-intensity physical activity (moderate time + [2 × vigorous time]) ≥150 min/week as assessed by the Global Physical Activity Questionnaire, or being a professional athlete
- Cigarette or vape smoking
- Intake of more than 14 alcoholic drinks per week
- Use of medications that may affect energy intake and/or expenditure, for example, semaglutide, liraglutide, exenatide, other GLP-1 receptor agonists, phentermine-topiramate, naltrexone-bupropion, orlistat, metformin, SGLT2 inhibitors, pramlintide, levocarnitine, amphetamines, and amphetamine-like drugs
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- Human immunodeficiency virus, galactosemia, and lactose intolerance
- Diseases that affect energy homeostasis including endocrine such as hypo/hyperthyroidism, or type 1 or 2 diabetes; cancer; chronic pulmonary diseases; cardiovascular disease; and renal disease
- History of inflammatory bowel disease (ulcerative colitis, Crohn's), malabsorption syndromes (intestinal, pancreatic), and sprue or gluten intolerance
- Having moderate to severe sleep apnea defined as an oxygen desaturation index \>10 times/hour assessed by overnight oximetry to be conducted on the night following the screening visit
- Use of oral hormonal contraceptives or less than 6 months using a hormonal intrauterine device (in women)
- Adults who are unable to consent
- Prisoners
- Currently pregnant or breastfeeding (in women)
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Pennington Biomedical Research Center
Baton Rouge, Louisiana, 70808
Rodrigo Fernández-Verdejo, PhD, 225-763-2594, rodrigo.fernandez@pbrc.edu
About this study
The regulation of human body weight and fatness is not fully understood. Although some models of regulation have been proposed (set point, dual-intervention point, others), no studies have been designed to test their predictions. In this pilot and feasibility study, the investigators will implement an experimental approach to test the predictions of models of body weight regulation in humans. Men and women with either low body weight or obesity will be exposed to a 2-day fasting followed by a 2-day ad-libitum refeeding. During the entire fasting-refeeding period, energy intake and expenditure will be accurately measured within metabolic chambers. The investigators will therefore determine the compensatory responses to fasting elicited to prevent weight loss. The results will serve to design and power future studies to better understand body weight regulation.
Read the detailed description
Background:
Although body weight regulation models have been proposed, experimental approaches for testing their predictions are lacking. The set point (SP) model proposes that a biologically determined fatness is defended by activating compensatory responses to prevent its change. The dual-intervention point (DIP) model proposes that there are two levels of fatness (lower and upper intervention points) within which fatness is weakly regulated. Compensatory responses would only be activated once the lower or upper intervention points are reached. In response to prolonged fasting, the SP model predicts the compensatory responses to be independent of the initial body weight. In contrast, the DIP model predicts higher responses in individuals who are closer to the lower intervention point (low body weight) compared to those who are farther away (obesity). None of these models predicts a different response in men vs. women. Our pilot and feasibility study will implement an experimental approach to test these predictions in humans by thoroughly measuring compensatory responses in energy expenditure and energy intake.
Design:
Twelve individuals (3 men with low body weight and 3 with obesity; 3 women with low body weight and 3 with obesity) will be kept inpatient in metabolic chambers for 5 consecutive days and exposed to a 1-day energy balance, 2-day fasting, and 2-day ad-libitum refeeding. The primary outcome will be the extent of compensatory response, calculated as the cumulative energy balance during the 5-day inpatient period.
Objectives:
- To determine the extent of compensatory response induced by a 2-day fasting followed by a 2-day ad-libitum refeeding in humans overall and among different subgroups (low body weight, obesity, men, women).
- To explore the timing of the compensatory responses during a 2-day fasting followed by a 2-day ad-libitum refeeding in humans.
- To explore potential physiological determinants of the inter-individual variability in the compensatory response induced by a 2-day fasting followed by a 2-day ad-libitum refeeding in humans.
Relevance:
Understanding how body weight is regulated in humans can help to prevent or treat obesity. In this pilot and feasibility study, the investigators propose an experimental approach to test the predictions of two body weight regulation models in response to fasting and explore potential sex differences. These preliminary data will be used to design and power future studies for testing models of body weight regulation in humans.
- Conditions
- Obesity, Underweight
- Being tested
- Fasting-refeeding cycle
- Keywords
- Energy expenditure, Energy intake, Energy balance, Set point model, Dual-intervention point model
- Medical subject headings
- Obesity, Thinness
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Fasting-refeeding cycleBehavioural
Participants will be maintained in metabolic chambers and exposed to 1 day of energy balance with a standard diet, 2 days of fasting (only water), and 2 days of ad-libitum refeeding using a liquid diet provided in hydration bladders to avoid portion control.
| Study group | Role | What they receive |
|---|---|---|
| Fasting-refeeding cycle | Experimental | Participants will be maintained in metabolic chambers and exposed to 1 day of energy balance, 2 days of fasting, and 2 days of ad-libitum refeeding. Receives: Behavioral: Fasting-refeeding cycle |
What is being measured
The primary outcome is the main question the study is designed to answer.
Compensatory response
Cumulative energy balance during the fasting-refeeding cycle
Measured: The cumulative energy balance is calculated one time using the data of 5 inpatient days
Secondary outcomes (12)
Timing of the compensatory response
Cumulative energy balance during different time periods of the 5-day fasting-refeeding cycle
Measured: The cumulative energy balance calculated for the following time periods along the 5-day fasting-refeeding cycle: day 1 to 2, day 1 to 3, day 1 to 4, during fasting (day 2 to 3), and during refeeding (day 4 to 5)
Protein balance
Protein balance (intake minus oxidation) during the fasting-refeeding cycle
Measured: Protein balance is calculated one time using the data of 5 inpatient days
Carbohydrate balance
Carbohydrate balance (intake minus oxidation) during the fasting-refeeding cycle
Measured: Carbohydrate balance is calculated one time using the data of 5 inpatient days
Lipid balance
Lipid balance (intake minus oxidation) during the fasting-refeeding cycle
Measured: Lipid balance is calculated one time using the data of 5 inpatient days
Overall appetite
Calculated from the results of visual analog scales that record hunger, satiety, fullness, and prospective food consumption
Measured: Overall appetite is measured 8 times per day (every 2 hours from approximately 8:00 AM) during the 5 inpatient days
Food preference
Measured using the Food Preference Questionnaire
Measured: Measured once a day, in the fasting state (at approximately 8:00 AM), during the 5 inpatient days
Physical activity
Measured with wrist-worn accelerometers
Measured: Measured continuously (i.e. for 24 hours) every day during the 5 inpatient days
Sleeping metabolic rate
Measured within the metabolic chamber, between 2:00 and 5:00 AM, and extrapolated to 24 hours
Measured: Measured every day during the 5 inpatient days
Leptin
Circulating concentrations of leptin
Measured: Measured once a day, in the fasting state (at approximately 8:00 AM), during the 5 inpatient days
Appetite-regulating hormones
Circulating concentrations of ghrelin and insulin
Measured: Measured once a day, in the fasting state (at approximately 8:00 AM), during the 5 inpatient days
Metabolites
Circulating concentrations of glucose, fatty acids, ketone bodies
Measured: Measured once a day, in the fasting state (at approximately 8:00 AM), during the 5 inpatient days
Thyroid axis
Circulating concentrations of T4
Measured: Measured once a day, in the fasting state (at approximately 8:00 AM), during the 5 inpatient days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted13 Mar 2024
- Study start17 Jan 2025
- Primary completion1 Oct 2026 (estimated)
- Study completion3 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for ObesityStudies of the same condition, open and under way.
- 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
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 12 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Pennington Biomedical Research Center
- Sponsor type
- University, hospital or other
- Collaborators
- Tulane University
- Responsible party
- Principal investigator, Eric Ravussin, Pennington Biomedical Research Center
- Investigators
- Rodrigo Fernandez-Verdejo, PhD, Principal investigator, Pennington Biomedical Research CenterEric Ravussin, PhD, Principal investigator, Pennington Biomedical Research CenterDragana Lovre, MD, Principal investigator, Tulane University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06309576
- Sponsor's protocol ID
- PBRC 2023-069
- Acronym
- DIP
- Status last verified
- May 2026
- First submitted
- 1 Mar 2024
- Last updated
- 29 May 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: The de-identified data collected will be shared upon appropriate request as part of the NORC repository of Pennington Biomedical Research Center
Study at a glance
From the registry record, last updated by the sponsor on 29 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Experimental Approach to Test Predictions of Body Weight Regulation Models
- ClinicalTrials.gov ID
- NCT06309576
- Acronym / sponsor ID
- DIP / PBRC 2023-069
- Conditions
- Obesity, Underweight
- Keywords
- Energy expenditure, Energy intake, Energy balance, Set point model, Dual-intervention point model
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 12 participants (estimated)
- Lead sponsor
- Pennington Biomedical Research CenterUniversity, hospital or other
- Collaborators
- Tulane University
- Study start
- 17 Jan 2025 (actual)
- Primary completion
- 1 Oct 2026 (estimated)
- Study completion
- 3 Dec 2026 (estimated)
- First posted
- 13 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.
The regulation of human body weight and fatness is not fully understood. Although some models of regulation have been proposed (set point, dual-intervention point, others), no studies have been designed to test their predictions. In this pilot and feasibility study, the investigators will implement an experimental approach to test the predictions of models of body weight regulation in humans. Men and women with either low body weight or obesity will be exposed to a 2-day fasting followed by a 2-day ad-libitum refeeding. During the entire fasting-refeeding period, energy intake and expenditure will be accurately measured within metabolic chambers. The investigators will therefore determine the compensatory responses to fasting elicited to prevent weight loss. The results will serve to design and power future studies to better understand body weight regulation.
Detailed description
Background:
Although body weight regulation models have been proposed, experimental approaches for testing their predictions are lacking. The set point (SP) model proposes that a biologically determined fatness is defended by activating compensatory responses to prevent its change. The dual-intervention point (DIP) model proposes that there are two levels of fatness (lower and upper intervention points) within which fatness is weakly regulated. Compensatory responses would only be activated once the lower or upper intervention points are reached. In response to prolonged fasting, the SP model predicts the compensatory responses to be independent of the initial body weight. In contrast, the DIP model predicts higher responses in individuals who are closer to the lower intervention point (low body weight) compared to those who are farther away (obesity). None of these models predicts a different response in men vs. women. Our pilot and feasibility study will implement an experimental approach to test these predictions in humans by thoroughly measuring compensatory responses in energy expenditure and energy intake.
Design:
Twelve individuals (3 men with low body weight and 3 with obesity; 3 women with low body weight and 3 with obesity) will be kept inpatient in metabolic chambers for 5 consecutive days and exposed to a 1-day energy balance, 2-day fasting, and 2-day ad-libitum refeeding. The primary outcome will be the extent of compensatory response, calculated as the cumulative energy balance during the 5-day inpatient period.
Objectives:
- To determine the extent of compensatory response induced by a 2-day fasting followed by a 2-day ad-libitum refeeding in humans overall and among different subgroups (low body weight, obesity, men, women).
- To explore the timing of the compensatory responses during a 2-day fasting followed by a 2-day ad-libitum refeeding in humans.
- To explore potential physiological determinants of the inter-individual variability in the compensatory response induced by a 2-day fasting followed by a 2-day ad-libitum refeeding in humans.
Relevance:
Understanding how body weight is regulated in humans can help to prevent or treat obesity. In this pilot and feasibility study, the investigators propose an experimental approach to test the predictions of two body weight regulation models in response to fasting and explore potential sex differences. These preliminary data will be used to design and power future studies for testing models of body weight regulation in humans.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Fasting-refeeding cycle | Experimental | Behavioral: Fasting-refeeding cycleParticipants will be maintained in metabolic chambers and exposed to 1 day of energy balance, 2 days of fasting, and 2 days of ad-libitum refeeding. |
Who may qualify
- Ages
- 18 to 40 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (7 listed)
- Body mass index lower than 20 kg/m2 for the low body weight group, or 30 kg/m2 or greater for the obesity group
- 18-40 years old
- Nulliparous and regular menstrual cycle (25-35 days) during the last six months (in women)
- Normal thyroid function, blood count, and chemistry 15 panel (normal plasma glucose will be considered at <100 mg/dL; normal serum HDL cholesterol at >=50 mg/dL for women and >=40 mg/dL for men; and normal serum triglycerides at <150 mg/dL).
- Self-reported weight stability during the last six months (±3 kg)
Key exclusion criteria (14 listed)
- Eating disorders as indicated by a global score ≥2.80 in the Eating Disorder Examination Questionnaire, or a previous diagnosis of an eating disorder
- For the low body weight group, having food insecurity (with or without hunger) as assessed by the USDA
- Recreational moderate-intensity physical activity ≥150 min/week, recreational vigorous-intensity physical activity ≥75 min/week, or a combination of recreational moderate-intensity and vigorous-intensity physical activity (moderate time + [2 × vigorous time]) ≥150 min/week as assessed by the Global Physical Activity Questionnaire, or being a professional athlete
- Cigarette or vape smoking
- Intake of more than 14 alcoholic drinks per week
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 |
|---|---|---|
| Fasting-refeeding cycleParticipants will be maintained in metabolic chambers and exposed to 1 day of energy balance with a standard diet, 2 days of fasting (only water), and 2 days of ad-libitum refeeding using a liquid diet provided in hydration bladders to avoid portion control. | Behavioural | Fasting-refeeding cycle |
Primary outcome
Compensatory response
Time frame: The cumulative energy balance is calculated one time using the data of 5 inpatient days
Cumulative energy balance during the fasting-refeeding cycle
12 secondary outcomes
Timing of the compensatory response
Time frame: The cumulative energy balance calculated for the following time periods along the 5-day fasting-refeeding cycle: day 1 to 2, day 1 to 3, day 1 to 4, during fasting (day 2 to 3), and during refeeding (day 4 to 5)
Protein balance
Time frame: Protein balance is calculated one time using the data of 5 inpatient days
Carbohydrate balance
Time frame: Carbohydrate balance is calculated one time using the data of 5 inpatient days
Lipid balance
Time frame: Lipid balance is calculated one time using the data of 5 inpatient days
Overall appetite
Time frame: Overall appetite is measured 8 times per day (every 2 hours from approximately 8:00 AM) during the 5 inpatient days
Food preference
Time frame: Measured once a day, in the fasting state (at approximately 8:00 AM), during the 5 inpatient days
Physical activity
Time frame: Measured continuously (i.e. for 24 hours) every day during the 5 inpatient days
Sleeping metabolic rate
Time frame: Measured every day during the 5 inpatient days
Leptin
Time frame: Measured once a day, in the fasting state (at approximately 8:00 AM), during the 5 inpatient days
Appetite-regulating hormones
Time frame: Measured once a day, in the fasting state (at approximately 8:00 AM), during the 5 inpatient days
Metabolites
Time frame: Measured once a day, in the fasting state (at approximately 8:00 AM), during the 5 inpatient days
Thyroid axis
Time frame: Measured once a day, in the fasting state (at approximately 8:00 AM), during the 5 inpatient days
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 29 May 2026.
- Individual participant dataSharing planned: Yes. The de-identified data collected will be shared upon appropriate request as part of the NORC repository of Pennington Biomedical Research Center
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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.
Rodrigo Fernandez-Verdejo, PhD principal investigator
Pennington Biomedical Research Center
Eric Ravussin, PhD principal investigator
Pennington Biomedical Research Center
Dragana Lovre, MD principal investigator
Tulane University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Fasting-refeeding cycle in people with Obesity and Underweight, run by Pennington Biomedical Research Center 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 7 inclusion and 14 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 29 May 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?
Contact Rodrigo Fernandez-Verdejo, PhD (2257632594, Rodrigo.Fernandez@pbrc.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Compensatory response (time frame: The cumulative energy balance is calculated one time using the data of 5 inpatient days). 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 29 May 2026.