From molecular structure to metabolic regulation: How natural polysaccharides combat obesity via multiple pathways

Obesity poses a pressing global health challenge, driving the search for safe and effective therapeutic strategies. Natural polysaccharides have emerged as promising anti-obesity agents due to their multifaceted bioactivities and favorable safety profiles. This review comprehensively summarizes the multi-target mechanisms underlying the anti-obesity effects of polysaccharides, including thermogenesis activation, adipogenesis suppression, lipid catabolism promotion, and gut microbiota modulation via prebiotic activity. Furthermore, we critically analyze the structure-activity relationships (SARs), highlighting how key structural features (molecular weight, monosaccharide composition, and chain conformation) dictate their biological efficacy. From an applied perspective, we also discuss the innovative utilization of polysaccharides as functional fat substitutes in healthier food formulations (e.g., dairy, meat, and bakery products). By integrating mechanistic insights with translational applications, this review provides a theoretical framework and practical guidance for designing polysaccharide-based functional foods to combat obesity.