Banana Resistant Starch Dose-Dependently Attenuates Obesity-Associated Metabolic Disturbances and Modulates Gut Microbiota in High-Fat-Diet-Fed C57BL/6J Mice

Background: With the rising prevalence of obesity and its cardiometabolic complications, there is increasing demand for safe and affordable dietary approaches that can counteract excessive adiposity and related metabolic dysfunction. Resistant starch (RS), which bypasses digestion in the upper gastrointestinal tract and is subsequently fermented by colonic bacteria, has emerged as a bioactive food component with reported benefits for glucose homeostasis, lipid profiles, and intestinal health. Methods: Here, we assessed whether green banana powder rich in RS2, incorporated into a high-fat diet at calculated RS contents of 5%, 10%, or 15% (w/w), could mitigate metabolic disturbances in C57BL/6J mice over an 8-week feeding period. Results: Relative to the high-fat diet alone, supplementation with the RS-rich banana powder produced dose-related improvements in body-weight trajectory, fasting glycemia and hyperinsulinemia, circulating TC/TG/LDL-C, glucose clearance (OGTT), and histologic features of hepatic lipid accumulation and adipocyte enlargement; the 15% dose most closely approximated the normal-diet phenotype. Fecal 16S rRNA profiling showed that community composition differed significantly among groups (ANOSIM R = 0.404, p = 0.001). Conclusions: Collectively, these data indicate that the RS-rich banana powder ameliorates several high-fat-diet-induced metabolic derangements in parallel with measurable shifts in gut microbial ecology, supporting its further evaluation as a candidate functional food ingredient for obesity prevention.