Obesity and COPD are increasingly common and often coexist, worsening health outcomes such as reduced lung function, exercise capacity, and increased systemic inflammation. While COPD was historically associated with underweight, obesity is now more prevalent among these patients and poses new challenges. Despite some evidence that weight loss may improve lung function, comprehensive interventions have not been fully studied.

The TRIO-COPD study aims to evaluate a 20-week program combining energy restriction, adequate protein intake, and structured exercise in COPD patients with obesity. The study will assess:

Primary outcome:

-Exercise capacity (6-minute walking test).

Secondary outcomes:

-Lung function (spirometry and lung volumes), -symptoms ( assessed via questionnaires), body composition (fat mass, fat-free mass, waist circumference), and inflammatory markers (e.g., IL-6, CRP, CC16).

A subgroup will also undergo sputum analysis.

The study addresses a critical gap, aiming to determine whether structured weight reduction can improve COPD symptoms, reduce inflammation, and limit muscle loss-advancing understanding of obesity's impact on COPD and providing evidence for potential treatment guidelines.

Inclusion Criteria:

• Individuals with COPD, defined by the GOLD criteria, with a forced expiratory volume in one second (FEV1) < 80% of predicted and a forced expiratory ratio of <70, with a BMI ≥ 30 kg/m2

Exclusion Criteria:

• patients with untreated cardiac disease, renal or hepatic failure, active cancer treatment, diabetes mellitus with prescribed insulin or patients with reported unintentional weight loss in the previous three months, or physical impairment that might affect the exercise capacity.

Will be added later

Investigator not taking part of the intervention will provide randomisation to start with diet or control