**1. Introduction**

Diabetes mellitus is described by high blood glucose level resulting from deficiencies in insulin secretion, insulin action, or both. Insulin is a hormone that is essential for the use or storage of body fuels that are Saccharide, protein, and fat. Beta-cells of the pancreas produce insulin. Persons with diabetes do not produce sufficient insulin; hyperglycemia (elevated blood glucose) occurs with insulin shortage [1] This chapter provides nutritional information regarding nutrients requirement, glycemic content of several foods, adjusting food's saccharide according to the insulin doses, medical nutrition therapy, idea about saccharide count for type 1 diabetic persons, management of blood glucose during exercise, and management of type 1 patient during sick days. This chapter would be helpful for type 1 patients and their caretaker, nutritionist, nurses, and doctors.
