Effective management of type 2 diabetes mellitus (T2DM) in older adults requires interventions that address both metabolic control and functional capacity. Exercise improves insulin sensitivity, glucose uptake and cardiometabolic health, while high-protein diets support muscle mass preservation, satiety and glycaemic regulation. Evidence suggests that integrating structured exercise with a high-protein diet may provide additive benefits; however, research evaluating this combined approach in older adults with T2DM, particularly in low-resource settings, is limited. This study aims to determine whether a 12-week multimodal exercise programme combined with a high-protein diet improves glycaemic control and broader health outcomes compared with exercise alone.

In this randomised controlled trial (RCT), 140 adults aged ≥60 years with T2DM will be allocated 1:1 to an experimental group (multimodal exercise with high-protein diet, n=70) or a control group (multimodal exercise alone, n=70). All participants will engage in three supervised exercise sessions per week for 12 weeks. Additionally, the experimental group will follow a high-protein diet that provides approximately 30% of total energy from protein, with a 500-kcal daily energy deficit. The primary outcome is glycaemic control, measured by Glycated haemoglobin (HbA1c). Secondary outcomes include anthropometric measures, fasting blood glucose, lipid profile, functional capacity (6-minute walk test) and health-related quality of life Short Form-36 Health Survey (SF-36). All outcomes will be assessed at baseline, postintervention (week 12) and follow-up (week 24). Participants, outcome assessors and statisticians will remain blinded. Intervention fidelity, adherence and safety will be systematically monitored, and final results will be analysed using SPSS (v.26.0). The study will follow ethical standards and comply with Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) and Consolidated Standards of Reporting Trials (CONSORT) guidelines.

The protocol has been approved by the Institutional Review Board of the Department of Physiotherapy and Rehabilitation, Jashore University of Science and Technology (Approval No.: PTR-JUST/IRB/2025/09/192404) and registered with the Clinical Trials Registry of India. Findings will be disseminated via peer-reviewed journals, conference presentations and structured knowledge-sharing sessions to inform clinical practice in diabetes management.

Trial registration number: CTRI/2025/08/092509