Abstract
High-fat (HF) diets contribute to obesity, insulin resistance, fatty liver, gut microbiota dysbiosis, oxidative stress, and low-grade chronic inflammation. This study evaluated the preventive effects of dietary Type 2 resistant starch (RS2) from high-amylose maize and low-dose d-fagomine (FG) from buckwheat on these metabolic disturbances. Male Wistar-Kyoto rats (9-10 weeks old) were assigned to four diet groups for 10 weeks: standard (STD) diet, HF diet (45% kcal from fat), HF + RS diet (15% RS2), and HF + FG diet (0.1% FG). Body characteristics, metabolic parameters, oxidative stress, gut microbiota, short-chain fatty acids (SCFAs), and eicosanoids were analyzed. Both HF + RS and HF + FG diets reduced perigonadal fat, plasma triacylglycerols, and oxidative stress. HF + RS diet improved glucose tolerance without significantly affecting insulin sensitivity, while HF + FG diet showed a tendency for improvement at later stages. Additionally, HF + RS diet showed greater beneficial effects on body weight and liver steatosis than HF + FG diet, likely due to gut microbiota and SCFA modulation. RS2 exerted stronger metabolic effects than FG under HF diet conditions, suggesting its greater potential in mitigating obesity-related complications. FG effects may require longer exposure to manifest.