Ketogenic Dietary Intervention in Men With Mild-to-Moderate COPD (COPDKETO)

June 18, 2026 updated by: Dursun Alper YILMAZ, Agri Ibrahim Cecen University

Effects of an 8-Week Ketogenic Dietary Intervention on Pulmonary Function, Systemic Inflammation, Body Composition, and Functional Exercise Capacity in Men With Mild-to-Moderate Chronic Obstructive Pulmonary Disease: A Pilot Randomized Controlled Trial

Chronic obstructive pulmonary disease (COPD) is associated with persistent airflow limitation, systemic inflammation, reduced exercise capacity, and unfavorable changes in body composition. Nutritional interventions may represent a complementary strategy to improve clinical outcomes in individuals with COPD.

This pilot randomized controlled trial evaluates the feasibility, safety, and preliminary effectiveness of an 8-week ketogenic dietary intervention in men with mild-to-moderate COPD. Participants are randomly assigned to either a supervised ketogenic diet or a control group receiving standard dietary advice. The ketogenic diet restricts carbohydrate intake and promotes nutritional ketosis, which is monitored using blood beta-hydroxybutyrate measurements.

The primary outcome is change in the FEV1/FVC ratio. Secondary outcomes include systemic inflammation assessed by C-reactive protein (CRP), phase angle measured by bioelectrical impedance analysis, functional exercise capacity assessed by the 6-minute walk test, estimated aerobic capacity, body composition, and selected biochemical safety markers. The study aims to provide preliminary evidence regarding whether a ketogenic dietary approach may improve inflammatory status, functional capacity, and physiological outcomes in individuals with COPD.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Chronic obstructive pulmonary disease (COPD) is a progressive respiratory disorder characterized by persistent airflow limitation, chronic inflammation, exercise intolerance, and alterations in body composition. In addition to pulmonary impairment, systemic manifestations such as increased inflammatory burden, skeletal muscle dysfunction, and adverse metabolic changes contribute substantially to morbidity and reduced quality of life. Nutritional interventions have therefore emerged as potential adjunctive strategies in COPD management.

Ketogenic diets are characterized by marked carbohydrate restriction, moderate protein intake, and increased dietary fat consumption, resulting in nutritional ketosis. Potential mechanisms relevant to COPD include reductions in systemic inflammation, changes in substrate utilization, reductions in adiposity, and alterations in respiratory gas exchange. However, randomized controlled studies investigating ketogenic dietary interventions in COPD remain limited.

This study is an 8-week, single-center, parallel-group pilot randomized controlled trial conducted in clinically stable men with GOLD stage I-II COPD. Participants are randomly allocated in a 1:1 ratio to either a ketogenic dietary intervention or a control group receiving standard dietary advice. The ketogenic diet is individually prescribed by a dietitian and aims to provide approximately 60-70% of total energy from fat, 15-20% from protein, and 5-10% from carbohydrates, with carbohydrate intake restricted to less than 50 g/day.

Nutritional ketosis is monitored using capillary beta-hydroxybutyrate measurements obtained throughout the intervention period. Pulmonary function is assessed using spirometry. Body composition and phase angle are measured using multifrequency bioelectrical impedance analysis. Functional exercise capacity is evaluated using the 6-minute walk test, and estimated aerobic capacity is derived from walking performance. Blood samples are collected to assess inflammatory and safety-related biomarkers, including C-reactive protein, lipid parameters, alanine aminotransferase, and creatinine.

The primary objective is to determine whether an 8-week ketogenic dietary intervention improves FEV1/FVC compared with standard dietary advice. Secondary objectives are to evaluate effects on systemic inflammation, phase angle, exercise capacity, body composition, and biochemical safety outcomes. As a pilot trial, the study is designed to generate effect-size estimates, assess feasibility and adherence, and inform the design of future larger multicenter randomized controlled trials.

Study Type

Interventional

Enrollment (Actual)

34

Phase

  • 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

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

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Male sex
  • Age between 40 and 75 years
  • Clinically stable chronic obstructive pulmonary disease (COPD)
  • GOLD stage I or II COPD
  • No acute COPD exacerbation within the previous 3 months
  • Stable pharmacological treatment for at least 4 weeks before enrollment
  • Ability to complete study assessments and comply with dietary instructions
  • Provision of written informed consent

Exclusion Criteria:

  • GOLD stage III or IV COPD
  • Uncontrolled cardiovascular disease
  • Chronic kidney disease
  • Severe hepatic dysfunction
  • Active malignancy
  • Insulin-dependent diabetes mellitus
  • Participation in another dietary intervention program within the previous 3 months
  • Inability to complete study assessments
  • Contraindications to dietary carbohydrate restriction
  • Refusal or inability to provide informed consent

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: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Ketogenic Diet
Participants received an individualized ketogenic dietary intervention for 8 weeks. The dietary prescription provided approximately 60-70% of total energy from fat, 15-20% from protein, and 5-10% from carbohydrates, with carbohydrate intake restricted to less than 50 g/day. Nutritional ketosis was monitored using blood beta-hydroxybutyrate measurements.
Behavioral: Ketogenic diet
Participants received an individualized ketogenic dietary intervention for 8 weeks. The dietary prescription provided approximately 60-70% of total energy from fat, 15-20% from protein, and 5-10% from carbohydrates, with carbohydrate intake restricted to less than 50 g/day. Nutritional ketosis was monitored using blood beta-hydroxybutyrate measurements throughout the intervention period.
Active Comparator: Standard Dietary Advice
Participants received standard dietary recommendations for chronic obstructive pulmonary disease and were instructed to maintain their habitual dietary patterns throughout the 8-week study period.
Behavioral: Standard Dietary Advice
Participants received standard dietary recommendations for chronic obstructive pulmonary disease and were instructed to maintain their habitual dietary patterns during the 8-week study period.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
FEV1/FVC Ratio
Time Frame: Change in the ratio of forced expiratory volume in one second (FEV1) to forced vital capacity (FVC), assessed by spirometry after 8 weeks of intervention.
Baseline and Week 8
Change in the ratio of forced expiratory volume in one second (FEV1) to forced vital capacity (FVC), assessed by spirometry after 8 weeks of intervention.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
C-Reactive Protein (CRP)
Time Frame: Baseline and Week 8
Serum C-reactive protein concentration (mg/L) measured as a marker of systemic inflammation.
Baseline and Week 8
Phase Angle
Time Frame: Baseline and Week 8
Change in phase angle measured by multifrequency bioelectrical impedance analysis.
Baseline and Week 8
6-Minute Walk Distance
Time Frame: Baseline and Week 8
Change in functional exercise capacity assessed by the 6-minute walk test.
Baseline and Week 8
Body Mass Index
Time Frame: Baseline and Week 8
Baseline and Week 8Change in body mass index calculated as weight divided by height squared.
Baseline and Week 8
Fat Mass
Time Frame: Baseline and Week 8
Baseline and Week 8Change in body fat mass measured by bioelectrical impedance analysis.
Baseline and Week 8
Estimated VO2max
Time Frame: Baseline and Week 8
Baseline and Week 8Change in estimated maximal oxygen uptake derived from 6-minute walk performance.
Baseline and Week 8

Collaborators and Investigators

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

Sponsor

Agri Ibrahim Cecen University

Investigators

  • Study Chair: Dursun Alper YILMAZ, Ağrı İbrahim Çeçen Üniversitesi

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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)

August 15, 2025

Primary Completion (Actual)

March 15, 2026

Study Completion (Actual)

June 15, 2026

Study Registration Dates

First Submitted

June 15, 2026

First Submitted That Met QC Criteria

June 18, 2026

First Posted (Actual)

June 23, 2026

Study Record Updates

Last Update Posted (Actual)

June 23, 2026

Last Update Submitted That Met QC Criteria

June 18, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • AICU-COPD-KETO-RCT-2026
  • SABF.25.003 (Other Grant/Funding Number: Ağrı İbrahim Çeçen University Scientific Research Projects Unit (BAP))

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

IPD Plan Description

Individual participant data sharing has not yet been determined. Data sharing decisions will be made after publication of the primary study results and will be subject to institutional policies, ethical considerations, participant confidentiality requirements, and applicable data protection regulations.

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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