Lifestyle Interventions and Genetic Scores for Weight Management (ACTION)

November 9, 2026 updated by: Kalliopi G, National and Kapodistrian University of Athens

Lifestyle Interventions and Genetic Susceptibility in Body Mass Index Management: The ACTION Study

The ACTION (Genotype-tAilored exerCise inTerventION) study investigated whether genetic information related to obesity susceptibility and endurance capacity could be used to inform personalized lifestyle interventions aimed at improving body mass index (BMI) and participation in physical activity programs.

Adults with increased genetic susceptibility to obesity and low habitual physical activity were invited to participate in an eight-week lifestyle intervention combining dietary counseling with physical activity recommendations.

The intervention initially compared structured jogging with recommendations to increase habitual physical activity. Following the evaluation of intervention completion, the exercise strategy was modified for a subsequent group of participants, incorporating a Genetic Endurance Score (GES) to guide allocation to jogging or yoga.

The study evaluated changes in BMI and completion of the assigned exercise programs, exploring the feasibility of integrating genetic information into personalized lifestyle recommendations.

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

The ACTION (Genotype-tAilored exerCise inTerventION) study was designed to investigate the potential of integrating polygenic susceptibility to obesity and genetically predicted endurance capacity into lifestyle interventions for BMI management.

The study included an observational analysis of 918 genotyped Greek adults recruited during two consecutive study periods. A weighted BMI Genetic Risk Score (BMI-GRS), based on 97 genetic variants, was used to assess obesity susceptibility, while habitual physical activity was assessed using the International Physical Activity Questionnaire (IPAQ-Gr).

Adults with increased obesity-related genetic susceptibility were invited to participate in the intervention component. Enrollment was prioritized for individuals with BMI-GRS values above the 70th percentile and low habitual physical activity. A total of 198 participants were enrolled in eight-week lifestyle interventions across two sequential cohorts.

All intervention participants received a common genetic risk-adapted dietary program and individualized lifestyle counseling. Dietary recommendations emphasized healthy eating habits, reduced saturated fat and refined carbohydrate intake, increased dietary fiber and plant-based food consumption, and regular fish consumption.

In the initial intervention cohort (n=113), participants were systematically allocated according to enrollment order to structured jogging (n=77) or recommendations to increase habitual physical activity (n=36). The primary objective was to evaluate changes in BMI following eight weeks of intervention.

Following discontinuation of the initial intervention, exploratory analyses investigated the association between genetically predicted endurance capacity and exercise program completion. These observations motivated a modification of the intervention strategy.

In the subsequent cohort (n=85), exercise allocation was guided by a nine-variant Genetic Endurance Score (GES). Participants with GES ≥50 were assigned to structured jogging (n=35), while those with GES <50 were assigned to structured yoga (n=50). This phase assessed eight-week intervention completion and short-term BMI change.

BMI was calculated from measured weight and height. Intervention completion was defined by completion of the assigned eight-week program and attendance at the final assessment. Discontinuation of the intervention was recorded.

Comparisons between the sequential intervention cohorts were considered exploratory because the cohorts were recruited at different times and exercise allocation procedures differed. The genotype-guided allocation strategy was developed following observations from the initial intervention and was not part of the original intervention design.

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.
198

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

  • Greece
    • Attica
      • Athens, Attica, Greece, 11527
        • National and Kapodistrian University of Athens, School of Medicine

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

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:Inclusion Criteria:

  • Adults aged 18 years or older.
  • Greek residents who had previously undergone genome-wide genotyping and baseline anthropometric and lifestyle assessment.
  • Elevated genetic susceptibility to obesity, defined by the High or Max BMI Genetic Risk Score (BMI-GRS) categories.
  • Low habitual physical activity at baseline.
  • Voluntary agreement to participate in an eight-week lifestyle intervention.
  • Enrollment was prioritized for individuals with BMI-GRS values above the 70th percentile when the number of eligible volunteers exceeded the available intervention capacity.

Exclusion Criteria:

  • Missing anthropometric measurements or essential baseline covariate data.
  • Body-weight change greater than 3% during the preceding three months.
  • Previous bariatric surgery.
  • Untreated psychiatric disorders.
  • Use of medications known to influence body weight.
  • For the initial intervention cohort, habitual participation in jogging at baseline.

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: Treatment
  • Allocation: Non-Randomized
  • Interventional Model: Parallel 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.
Experimental: Structured Jogging

Participants assigned to structured jogging followed an eight-week exercise program together with common genetic risk-adapted dietary counseling. This arm included 77 participants from the initial cohort, allocated systematically by enrollment order, and 35 participants from the subsequent cohort, allocated according to a Genetic Endurance Score (GES) ≥50. A total of 112 participants received the jogging intervention.
Behavioral: Structured Jogging Program

An eight-week structured jogging program aimed at increasing weekly physical activity relative to baseline. The intervention was implemented in both sequential cohorts: 77 participants in the initial cohort and 35 participants with a Genetic Endurance Score (GES) ≥50 in the subsequent cohort. All participants also received common dietary counseling.

Behavioral: Genetic Risk-Adapted Dietary Counseling

All 198 intervention participants received a common eight-week genetic risk-adapted dietary counseling program designed to support gradual weight loss. Recommendations emphasized reducing saturated fat and refined carbohydrate intake, increasing dietary fiber and plant-based foods, regular fish consumption, and behavioral strategies to support dietary adherence. The same dietary protocol was applied in both sequential intervention cohorts.
Active Comparator: Cohort-Specific Physical Activity

This arm represents the alternative physical activity strategy used in each intervention cohort. In the initial cohort, 36 participants received recommendations to increase physical activity through their habitual activities. In the subsequent cohort, 50 participants with a Genetic Endurance Score (GES) <50 were assigned to structured yoga. Both groups received the common dietary counseling intervention for eight weeks. The two exercise strategies were implemented in separate, sequential cohorts and were not identical interventions.
Behavioral: Genetic Risk-Adapted Dietary Counseling

All 198 intervention participants received a common eight-week genetic risk-adapted dietary counseling program designed to support gradual weight loss. Recommendations emphasized reducing saturated fat and refined carbohydrate intake, increasing dietary fiber and plant-based foods, regular fish consumption, and behavioral strategies to support dietary adherence. The same dietary protocol was applied in both sequential intervention cohorts.

Behavioral: Habitual Physical Activity Recommendations

Participants received individualized recommendations to increase their weekly physical activity through their habitual forms of exercise, without assignment to a structured jogging or yoga program. This eight-week intervention was implemented in the initial cohort (n=36), alongside the common genetic risk-adapted dietary counseling program. Physical activity recommendations aimed to increase weekly activity relative to baseline.

Behavioral: Structured Yoga Program

An eight-week structured yoga program assigned to participants with a Genetic Endurance Score (GES) below 50. The intervention was implemented in the subsequent cohort (n=50) as an alternative to structured jogging for individuals with lower genetically predicted endurance capacity. All participants also received the common genetic risk-adapted dietary counseling program.

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
Percentage Change in Body Mass Index (BMI) From Baseline to Week 8
Time Frame: Baseline and Week 8

Percentage change in BMI was calculated as 100 × (baseline BMI - BMI at Week 8) / baseline BMI. Positive values indicate a decrease in BMI, whereas negative values indicate an increase. BMI was calculated from measured body weight (kg) divided by height squared (m²). The outcome was evaluated among participants who completed the eight-week intervention and had available follow-up anthropometric measurements.
Baseline and Week 8

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.
National and Kapodistrian University of Athens

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Kalliopi K Gkouskou, PhD, National and Kapodistrian University of Athens, School of Medicine
  • Study Chair: Aristides G Eliopoulos, PhD, National and Kapodistrian University of Athens, School of Medicine

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.
October 29, 2023

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.
December 22, 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.
December 22, 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).
November 1, 2026

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.
November 1, 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.
November 6, 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.
November 13, 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.
November 9, 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.
October 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.
  • ACTION-NKUA-001

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

There is currently no plan to share individual participant data. The study includes genetic and health-related information. Any future data sharing would be subject to applicable data protection requirements, participant consent provisions, and approval by the responsible institution.

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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