The diet schedule and food intake effect on body glucose is the key problem of the diabetic patient. For type 1 diabetic patients, it is necessary to optimize the diet schedule and insulin regimen to control the body glucose level in the postprandial state. Hence, a closed-loop system containing insulin delivery and diet schedule is required for type 1 diabetic patients. In the current paper, a mathematical model of glucose-insulin is proposed to investigate the glucose profile along with plasma insulin level for type 1 diabetic patients. Four different and most common cases have been considered with the scheduled plan of diet and insulin regimen to simulate the glucose profile along with plasma insulin level. The glucose-insulin model was simulated using MATLAB to investigate the artificial pancreas system. The analysis includes glucose absorption parameters and net hepatic glucose balance (NHGB). The results represent that the proposed mathematical model may be useful to predict the glycaemic status of diabetic patients and personalise it as per their historical data.