Nutritional Impairment and Muscle Health in MASLD: The Potential Role of Eating Behaviors

Obesity can conceal nutritional impairment and compromised muscle health in metabolic dysfunction-associated steatotic liver disease (MASLD). This critical narrative review examines the potential role of eating behaviors in nutritional impairment and muscle health in MASLD, focusing on adults with overweight or obesity while considering the limited findings in lean MASLD and, separately, pediatric evidence. Altered eating behaviors are associated with prevalent MASLD, but their contribution to malnutrition, myosteatosis, and sarcopenic obesity remains unproven. Nutritionally adverse dietary patterns and appetite loss may increase vulnerability, although evidence linking these factors to muscle outcomes derives predominantly from aging and general obesity populations. Total daily protein intake is better supported than specific meal-level distribution targets, while resistance exercise offers more consistent functional benefits than protein supplementation alone in the limited direct MASLD evidence. Restricting eating windows has not demonstrated additional hepatic benefit over usual care. Incretin-associated lean-mass loss does not by itself establish sarcopenia or disproportionate muscle harm and requires interpretation alongside muscle strength and function. Physical inactivity, socioeconomic circumstances, multimorbidity, and reverse causation complicate attribution to eating behavior. These findings support assessment beyond body mass index, integrating eating behaviors, nutritional risk, and muscle health. We propose an adult assessment framework; however, prospective studies are needed to validate it and clarify the independent contribution of eating behaviors to nutritional and muscle deterioration in MASLD.