Background: Cardiometabolic multimorbidity is rising globally and in Ethiopia, yet many patients still receive little or no structured dietary education in chronic care settings. Although nutrition counselling has been studied in single conditions such as diabetes or hypertension, no prior research has evaluated its effectiveness among patients with cardiometabolic multimorbidity. Because people living with multiple chronic diseases have more complex dietary needs and greater self-management challenges, evidence from single-disease groups cannot be assumed to apply to them. In Ethiopia, it remains unknown whether nutrition counselling can improve dietary adherence, clinical outcomes, or nutrition related quality of life in this population.

Objective: To examine the effect of nutrition counselling on dietary adherence, clinical outcomes, and nutrition related quality of life among patients with cardiometabolic multimorbidity in South Wollo, Northeast Ethiopia.

Methods: A two-arm, parallel, cluster randomized controlled trial across 14 hospitals, with seven hospitals assigned to the intervention arm and seven to the control arm will be conducted. Adult patients diagnosed with two chronic conditions (type 2 diabetes and hypertension) will be recruited using systematic random sampling, resulting in a total sample size of 308 participants. The intervention group will receive nutrition counselling guided by the COM-B Model and adapted from national and international dietary guidelines. Six individualized counselling sessions will be delivered over a period of three months. The control group will continue to receive routine care. Dietary adherence, clinical parametres, and nutrition related quality of life will be outcome variables. Generalized structural equation modeling will be used to analyze dietary adherence, while structural equation modeling will be applied for clinical parametres and nutrition related quality of life. Results will be presented as adjusted estimates with 95% confidence intervals.

Expected outcomes: This study is expected to generate evidence showing whether nutrition counselling can improve dietary adherence, clinical outcomes, and nutrition related quality of life among patients with cardiometabolic multimorbidity. The intervention is anticipated to enhance patients' dietary practices, support better control of blood pressure and fasting blood glucose, and contribute to improved quality of life.