High Fat Diet for Cardiac Metabolic Reprogramming

Inclusion Criteria: * Patients of both sexes and ≥18 years old * Patients diagnosed with HF secondary to non-ischemic DCM, according to ESC guidelines definition,1 with or without a known genetic basis. * LVEF ≤49% according to the baseline CMR. * Optimized HF guideline-directed medical therapy for at least 3 months prior to inclusion. * Patients who have provided informed consent. Exclusion Criteria: * Prior diagnosis of ischemic DCM. * Prior diagnosis of established atherosclerotic cardiovascular disease (angina/myocardial infarction, transient ischemic attack/stroke, lower limb ischemia or at any other peripheral level). * Changes in HF therapies within the last 3 months. * HF decompensation within the previous 3 months, including HF hospitalization or the need of ambulatory intravenous diuretic or inotropic treatment such as levosimendan. * Uncontrolled dyslipidemia, defined as LDL-cholesterol \>160 mg/dL and/or triglycerides \>200 mg/dL, despite treatment. * Any contraindication for CMR: Severe claustrophobia. Any device which is known to threaten or pose hazard in all MR environments. //www.mrisafety.com/ Patients with implanted biomedical devices (cardiac artefacts): pacemakers, cardiac defibrillators or cardiac resynchronization therapy. * Liver and biliary diseases, including prior diagnosis of non-alcoholic fatty liver disease and unoperated cholelithiasis. * Prior episodes of acute pancreatitis or chronic pancreatitis. * Prior fish or nut allergy. * Life expectancy less than 12 months. * Pregnancy or planned pregnancy for the next 4 months. * Current lactation. * Patients participating in other randomized clinical trial. * Impossibility to consent or undergo study follow-up