Type 1 diabetes mellitus is a serious autoimmune disease for which no cure is available. The treatment includes insulin therapy, carbohydrate counting, eating healthy foods, exercising regularly, and maintaining a healthy weight. The goal is to keep blood glucose levels close to normal most of the time to delay or prevent complications. Despite the increase in the use of insulin pumps and continuous glucose monitors in recent years, the management of type 1 diabetes remains suboptimal in terms of glycaemic control and normal glycated haemoglobin (HbA1c) level. This article discusses the case of a child with type 1 diabetes who was successfully treated with a very low-carbohydrate diet, resulting in normal levels of HbA1c and normal blood glucose 95% of the time in a range of 70–180 mg/dL (4.0 mmol/L−10 mmol/L). Therefore, further studies are needed to verify how a very low carbohydrate diet impacts child development.