Nutritional Strategies for Selected MASLD Outcomes: Metabolic Remodeling, Liver-Aging Biomarkers, and Public Health Priorities

Metabolic dysfunction-associated steatotic liver disease (MASLD) connects nutritional exposures with cardiometabolic risk and vulnerability during aging. Nutrition provides an actionable foundation for care, while metabolomics may clarify variation in dietary responses. This critical narrative review integrates nutritional trials, metabolic and aging studies, and clinical guidance from PubMed, Web of Science, Scopus, and Google Scholar through September 2026 using a documented narrative-search and selection process. Evidence is differentiated by population, original disease definition, design, tissue source, biomarker role, and outcome. Sustained weight reduction and selected dietary interventions, including Mediterranean-style and other high-quality dietary patterns, can improve selected hepatic or cardiometabolic outcomes, although comparative superiority is inconsistent. Lipid handling, nutrient sensing, mitochondrial function, and microbial metabolites provide mechanistic context. Metabolomic signatures characterize dietary exposure and metabolic adaptation, whereas direct evidence that nutritional treatment slows liver-specific biological aging remains absent: such evidence would require a defined MASLD population, a nutritional intervention, and a liver-tissue or independently validated liver-specific aging endpoint. Nutritional effects on aging measures are heterogeneous and largely derived from populations not selected for MASLD. The synthesis identifies public health priorities: reducing cumulative dietary risk, integrating nutritional care with fibrosis and cardiometabolic assessment, preserving muscle function, and expanding access to sustained support. A qualification framework distinguishes exposure, association, prognosis, response, and candidate surrogate roles while incorporating cost and equity. Accessible nutritional care can improve selected MASLD outcomes now; aging-informed precision nutrition remains investigational until molecular testing improves decisions and durable health benefits beyond established assessment.