Anti-Obesity Mechanisms of Plant and Fungal Polysaccharides: The Impact of Structural Diversity.

Obesity, a multifactorial metabolic syndrome driven by genetic-epigenetic crosstalk and environmental determinants, manifests through pathological adipocyte hyperplasia and ectopic lipid deposition. With the limitations of conventional anti-obesity therapies, which are characterized by transient efficacy and adverse pharmacological profiles, the scientific community has intensified efforts to develop plant and fungal polysaccharide therapeutic alternatives. These polysaccharide macromolecules have emerged as promising candidates because of their diverse biological activities and often act as natural prebiotics, exerting beneficial effects through multiple pathways. Plant and fungal polysaccharides can reduce blood glucose levels, alleviate inflammation and oxidative stress, modulate metabolic signaling pathways, inhibit nutrient absorption, and reshape gut microbial composition. These effects have been shown in cellular and animal models and are associated with mechanisms underlying obesity and related metabolic disorders. This review discusses the complexity of obesity and multifaceted role of plant and fungal polysaccharides in alleviating its symptoms and complications. Current knowledge on the anti-obesity properties of plant and fungal polysaccharides is also summarized. We highlight their regulatory effects, potential intervention pathways, and structure-function relationships, thereby providing novel insights into polysaccharide-based strategies for obesity management.