Systematic Review of the Effects of Plant-Based Foods on Metabolic Outcomes in Adults with MASLD and Comorbidities Such as Obesity, Metabolic Syndrome, and Type 2 Diabetes

Background: Metabolic dysfunction-associated steatotic liver disease (MASLD) has become one of the most prevalent liver diseases, affecting up to 40% of adults and strongly associated with obesity and metabolic dysfunction. Despite the lack of approved pharmacological treatments, dietary interventions with plant-based foods, including the Mediterranean diet (MED), rich in numerous bioactive compounds may offer benefits for metabolic health and hepatic function. However, the role of individual plant foods in MASLD management remains unclear. Objectives: This review investigates the effects of specific plant-based foods, consumed as part of the MED and Dietary Approaches to Stop Hypertension (DASHs) diet, on metabolic outcomes, including hepatic function, in MASLD patients alone or in combination with comorbidities such as obesity, metabolic syndrome, and type 2 diabetes mellitus (T2DM). Methods: A systematic search was registered and conducted across nine databases to identify randomized controlled trials (RCTs) carried out in adults with MASLD and published between January 2020 and May 2025, following PRISMA guidelines. Results: Plant-based interventions including oranges, whole-grain products (WGPs), high-fiber buns (HFBs), beetroot juice (BJ), garlic, ginger, flaxseed, spirulina, rapeseed oil, sour tea, and green coffee extract (GCE) demonstrated mixed effects on metabolic and hepatic outcomes. GCE, flaxseed, and rapeseed oil improved anthropometric measures, while sour tea and ginger supported blood pressure control. WGPs, GCE, flaxseed, rapeseed oil, spirulina, ginger, and garlic were beneficial for glycemic regulation, whereas WGPs, HFBs, BJ, golden flaxseed, rapeseed oil, and garlic improved lipid profiles. Liver enzymes improved following consumption of WGPs, BJ, sour tea, flaxseed oil, and garlic, and hepatic steatosis was reduced after intake of oranges, WGPs, HFBs, BJ, flaxseed powder, rapeseed oil, and garlic powder. Conversely, a solely fruit-rich diet (FRD) had negative effects across all outcomes. Conclusions: Plant-based foods improved metabolic outcomes, with WGPs, HFBs, beetroot, oranges, sour tea, flaxseed oil, and garlic providing specific benefits for liver health. Further research is needed to validate these effects and ensure their safety in MASLD management.