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A thermally processed cafeteria diet reproducibly mimics early metabolic syndrome through obesity, insulin resistance, and inflammatory activation in Wistar rats

Year: 2026

Type: article

Abstract: The obesogenic nutrient composition and processing characteristics of ultra-processed foods may contribute to metabolic dysfunction. The present study evaluated a standardized cafeteria diet, alone or combined with low-dose streptozotocin (STZ), in male Wistar rats. Animals (n = 32) were allocated to Healthy Control, STZ (35 mg/kg), Cafeteria Diet (CAF), and CAF + STZ groups. The diet contained standard chow, condensed milk, refined sugar, hydrogenated fat, soybean oil, and chocolate-filled biscuits, homogenized and thermally processed at 180°C. After 102 days, anthropometric, metabolic, inflammatory, gene expression, microbiota, and histopathological parameters were assessed. CAF induced a marked obesogenic phenotype, with increased body weight (+172.3%) and abdominal circumference (+38.7%; P < 0.01). CAF showed hyperglycemia (median glucose, 403 mg/dl) and higher HOMA-IR than Healthy Control (P < 0.01); CAF + STZ also showed increased HOMA-IR (P < 0.05). CAF increased IL-1β and IL-6 (P < 0.05), triglycerides, adipocyte hypertrophy (P < 0.01), and adipose leptin expression (P < 0.05), while reducing muscle Slc2a4/GLUT4 expression (P < 0.01). Liver, kidney, and pancreatic histopathological scores did not differ significantly. Gut microbiota showed marked compositional imbalance and low taxonomic evenness, with Firmicutes (99.83%), Ligilactobacillus (99.36%), and Lactobacillaceae (99.52%) predominating, while Enterobacteriaceae represented 0.14%. Despite no reduction in Shannon or Simpson indices, extreme Ligilactobacillus dominance indicated a restricted and uneven community. Overall, the cafeteria diet reproduced obesity-associated metabolic dysfunction, characterized by hyperglycemia, insulin resistance, inflammation, adipocyte hypertrophy, altered glucose and leptin expression, and substantial microbiota restructuring.

Source: Bioscience Reports

DOI: 10.1042/bsr20260388