Clinical Phenotypes and Personalized Nutritional Strategies in Metabolic Dysfunction-Associated Steatotic Liver Disease

Abstract

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a highly prevalent metabolic disorder characterized by substantial clinical heterogeneity and frequent association with obesity, insulin resistance, type 2 diabetes mellitus, dyslipidemia, visceral adiposity, and alterations in body composition. This study analyzed the principal clinical phenotypes of MASLD and their relationship with personalized nutritional interventions through a structured analytical review of clinical guidelines, systematic reviews, meta-analyses, randomized controlled trials, and observational studies. The evidence showed marked differences in disease prevalence and metabolic characteristics across lean, overweight, obese, and diabetic populations. Sustained weight loss was associated with progressive hepatic improvement, with reductions of approximately 5% linked to decreased liver fat, 7–10% to improvement in inflammatory activity, and reductions of 10% or greater to greater probability of fibrosis improvement. Dietary quality was also relevant independently of absolute weight reduction, particularly through Mediterranean-style patterns, reduced intake of added sugars and ultra-processed foods, and replacement of saturated fats with unsaturated sources. Lean MASLD represented a distinct phenotype in which metabolic dysfunction may persist despite normal body mass index, requiring greater emphasis on body composition, visceral adiposity, physical activity, and preservation of lean mass rather than aggressive caloric restriction. Overall, the findings support a phenotype-oriented model of nutritional management in which common evidence-based lifestyle principles are maintained while the intensity and priority of specific interventions are adapted to individual metabolic, hepatic, anthropometric, and behavioral characteristics. Further prospective studies are required to determine whether personalized nutritional strategies improve long-term fibrosis progression, cardiovascular outcomes, liver-related complications, and mortality.