To understand diabetes, you have to understand how the body digests food. Normally, eating triggers the pancreas to send out the right amount of insulin, so the body can convert the glucose in the food we eat into energy. This doesn’t happen in people with diabetes. In some forms of diabetes, the body doesn’t produce any insulin at all or produces so little that it can’t do its job. This is referred to as type 1 diabetes. In other cases, the body produces insulin but is unable to use it properly. This is called type 2 diabetes.

When glucose can’t enter the cells, it builds up in the blood. Eventually it flows into the urine and passes out of the body, depriving cells of their main source of fuel.

Type 1 diabetes affects about 5% to 10% of people with diabetes, and it is usually diagnosed during childhood or adolescence. Type 1 must be controlled with insulin injections in addition to meal plans and a program of regular activity.

Type 2 diabetes is responsible for about 90% of all cases of diabetes. Although it is most often diagnosed in people age 40 and over, it is becoming more common in younger people, possibly due to the growing number of overweight children. It can usually be controlled with a combination of diet, exercise, and oral medication; however, some people need insulin injections to control their blood sugar levels.

Gestational diabetes, also known as diabetes of pregnancy, happens in about 3% to 4% of pregnancies, and it can be harmful to both the mother and baby if it is not controlled. It usually disappears after the baby is born, but having gestational diabetes increases a woman’s risk of developing type 2 diabetes later in life.