Metabolic Flexibility and Metabolic Heath in Human Obesity (PROB)

February 24, 2026 updated by: Jose Galgani

Metabolic Flexibility, Eating Behavior and Adipose Tissue Expandability: Role of This Triad in the Propensity to Human Obesity

This interventional study explores the relationship between improvements in metabolic health following weight loss and changes in whole-body fat mass and its distribution. The study focuses on adult men and women with excess body weight undergoing dietary energy restriction over 12 weeks. The primary research question is: Does a greater reduction in fat mass for a given weight loss correlate with more significant improvements in metabolic health?

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Obesity is a well-established risk factor for disruptions in metabolic health, which often precede cardiovascular disease and type-2 diabetes. While the precise pathophysiological mechanisms linking obesity to these conditions remain unclear, it is widely acknowledged that an increase in fat mass plays a central role, including the expansion of adipose tissue and the accumulation of lipids in non-adipose tissues. As a result, a primary approach to improving metabolic health is to reduce fat mass through negative energy balance. However, lifestyle changes or pharmacological interventions aimed at inducing a negative energy balance do not exclusively target fat mass and often result in the loss of fat-free mass to varying degrees. Given that higher fat mass, rather than fat-free mass, is more strongly associated with impaired metabolic health, strategies that maximize fat mass loss while preserving fat-free mass may offer more significant benefits for metabolic health. Surprisingly, there is a lack of evidence to support this hypothesis. To address this gap, it will be evaluated the relationship between changes in metabolic health and body composition, independent of overall weight loss, in individuals with overweight or obesity undergoing dietary energy restriction. It is hypothesized that greater fat mass reduction will be linked to more substantial improvements in metabolic health for a given weight loss.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
74

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Chile
      • Santiago, Chile
        • Avda. Libertador Bernardo O´Higgins 340. Santiago. Chile.

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion criteria

  • males or females
  • 30-55 y old
  • physically inactive (<600 MET´min/wk of self-reported moderate-vigorous physical activity
  • stable body weight for at least the past 6 months (±2 kg)
  • healthy according to medical history and routine hematology and biochemistry.

Exclusion criteria

  • Individuals with physiological (pregnancy, lactation) or pathological (under drug therapy for and/or having cardiovascular, liver, kidney, thyroid diseases)
  • conditions affecting energy metabolism or eating behavior
  • Subjects having low-fat (<20% energy) or low-carbohydrate (<45% energy) diets
  • Smokers and alcohol abusers

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Other: Weight Loss Intervention
Individuals with overweight or obesity will undergo dietary energy restriction aimed to induce 8 to 12% weight loss after 12 weeks. For 3 to 5 weeks, body weight will be maintained.
Other: Body Weight Loss
Individuals will be prescribed a hypocaloric diet (1300 kcal/d). Individuals will receive a booklet detailing the type of meals and foods to be consumed in each mealtime. A dietitian will explain how to enhance dietary compliance. Every two weeks, body weight, vital signs, and adverse events will be monitored. In addition, food recalls will be conducted in order to optimize dietary energy restriction compliance. During weight maintenance, energy intake will be adjusted to energy requirements to maintain weight stability (±2.5 kg) for at least 3 weeks. During weight loss and maintenance, participants will be instructed to maintain their customary physical activity.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Fasting serum triglyceride concentration
Time Frame: From enrollment to the end of weight maintenance period at 15-20 weeks
In overnight fasted individuals, a blood sample will be drawn. Serum will be isolated and stored at -80C until assessment.
From enrollment to the end of weight maintenance period at 15-20 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
HOMA-IR
Time Frame: From enrollment to the end of weight maintenance period at 15-20 weeks.
In overnight fasted individuals, a blood sample will be drawn for glucose and insulin assessment. HOMA-IR will be calculated using this formula: (glucose, mM * insulin, uU/mL)/22.5. Serum/Plasma will be isolated and stored at -80C until assessment.
From enrollment to the end of weight maintenance period at 15-20 weeks.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Jose Galgani

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Agencia Nacional de Investigación y Desarrollo

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 23, 2022

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
January 6, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
January 6, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
July 25, 2025

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 12, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
January 21, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
February 27, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 24, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 200602001

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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