Comparative effects of ketogenic and carbohydrate loading diets on body weight management and glycemic control in male obese diabetic rats

Abstract Background Obesity is one of the catastrophic metabolic disorders. Ketogenic diet and carbohydrate loading system are considered promising strategies for obesity management. The present study aims to compare both techniques in controlling obesity and diabetes in male albino rats. Thirty-six male albino rats were randomly divided into four equal groups; the control group fed on standard rodent diet (STD) for 9 consecutive weeks. The second, third, and fourth groups fed on high-fat diet (HFD) for five consecutive weeks. In the fourth week, the last three groups were injected with a single dose of streptozotocin (30 mg STZ/kg), for induction of type 2 diabetes mellitus. From the fifth week till the end of experiment, rats of the last two groups received either ketogenic diet (KD) or carbohydrate loading diet (CLD). The hepatic and pancreatic levels of malondialdehyde (MDA), and glutathione (GSH) and activity of superoxide dismutase (SOD) were analyzed. Gene expression of adiponectin and leptin was assessed in the adipose tissue. The serum levels of glucose, insulin, total cholesterol (TC), low- and high-density lipoprotein cholesterol (LDL-C & HDL-C), triglycerides (TG), and alanine and aspartate aminotransferase (ALT & AST) were detected. The liver and pancreas were histologically investigated. Results Rats STZ + HFD group showed increased body weight, feed and water intake, elevated liver, kidney, and adipose tissue relative weights, hepatic and pancreatic lipid peroxidation, disrupted liver and pancreatic histology, and worsened serum glucose and lipid profiles. The STZ + KD group showed initial increase in body weight but later reduced, compared to STZ + HFD group, with increased hepatic and adipose tissue relative weights with severe oxidative damage in both tissues. The glucose and insulin levels were significantly adjusted compared to STZ + HFD group but still far from the controls. The STZ + CLD group showed no significant organ weight changes, reduced oxidative stress, improved insulin activity, better lipid profiles, and preserved liver and pancreatic histology, indicating protective effects against HFD-induced metabolic and tissue damage. Conclusion The CLD effectively protected against HFD-induced oxidative damage and more efficiently controlled obesity, hyperglycemia, and hyperinsulinemia in rats compared to the KD, indicating the superior protective and metabolic regulatory effects of CLD over KD.