Inulin, a plant polysaccharide, is not digestible by human gut enzymes but is fermented by certain bacteria in the human microbiota, acting as a prebiotic. Its consumption has been linked to changes in the intestinal microbiota that improve metabolic health, particularly in obesity-related conditions. This review examines the main effects of inulin on human metabolic health and the mechanisms of its action. Inulin supplementation is associated with improved body weight and BMI control, reduced blood glucose levels, enhanced insulin sensitivity, and decreased inflammation markers. These effects are primarily mediated through the selective promotion of short-chain fatty acid (SCFA)-producing bacteria, such as *Bifidobacterium* and *Anaerostipes*. SCFAs produced during inulin fermentation have been shown to ameliorate glucose metabolism, reduce hepatic lipogenesis, and modulate immune activity. The review also discusses the potential of inulin in combination with other compounds and its effects on other diseases, such as chronic kidney disease and inflammatory bowel diseases. Overall, the findings suggest that inulin intake can produce positive metabolic effects by improving the intestinal microbiota and the metabolites produced by its fermentation.Inulin, a plant polysaccharide, is not digestible by human gut enzymes but is fermented by certain bacteria in the human microbiota, acting as a prebiotic. Its consumption has been linked to changes in the intestinal microbiota that improve metabolic health, particularly in obesity-related conditions. This review examines the main effects of inulin on human metabolic health and the mechanisms of its action. Inulin supplementation is associated with improved body weight and BMI control, reduced blood glucose levels, enhanced insulin sensitivity, and decreased inflammation markers. These effects are primarily mediated through the selective promotion of short-chain fatty acid (SCFA)-producing bacteria, such as *Bifidobacterium* and *Anaerostipes*. SCFAs produced during inulin fermentation have been shown to ameliorate glucose metabolism, reduce hepatic lipogenesis, and modulate immune activity. The review also discusses the potential of inulin in combination with other compounds and its effects on other diseases, such as chronic kidney disease and inflammatory bowel diseases. Overall, the findings suggest that inulin intake can produce positive metabolic effects by improving the intestinal microbiota and the metabolites produced by its fermentation.