Objective: Type I diabetes is a disease characterised by an extreme reduction in serum insulin levels. Diet and exercise have gained considerable attention in the treatment of diabetes. Therefore, this study was carried out to investigate the effect of diet with carbohydrate but without daily energy restriction on various metabolites (glucose, triglycerides, cholesterol, lactate), some electrolytes (Ca, Mg, Na, K, P, Cl) and essential metals (Mn, Co, Cu, Se, Zn, Fe) in the blood of rats with streptozotocin-induced diabetes. Materials and methods: Thirty-three male rats were divided into four groups of standard rat diet (SR)-fed control, SR-diet fed diabetics, low carbohydrate-standard protein-high fat (LCSPHF) diet-fed diabetics, and very low carbohydrate-high protein-high fat (VLCHPHF) diet-fed diabetics. Diabetes was induced by an i.p. injection of 50 mg/kg streptozotocin. The rats were fed with the specially prepared diets for 28 days. Results: The decreased-serum Cl and the increased-serum glucose levels were only the difference between the controls and SR diet-fed diabetic rats regarding to measured parameters. Lowering carbohydrate and increasing fat ratio in diet caused an increase in serum cholesterol and triglyceride levels leading to an increased-serum Fe and Ca, and decreased-serum Na and Cu levels in diabetic rats. Conclusion: The serum mineral changes should be taken into consideration together with the changes in serum glucose, cholesterol, and triglyceride levels for the secondary complications of diabetes mellitus. [ABSTRACT FROM AUTHOR]