Diabetes is a condition of elevated blood sugars where the body does not produce enough insulin to meet the body's needs or the body does not respond properly to the insulin being made. Insulin is important because it moves glucose (or sugar) into the body's cells from the blood. It also has a number of other effects on metabolism.

The medical name of this condition is diabetes mellitus. It is sometimes referred to as "sugar diabetes." There is another form of diabetes, called diabetes insipidus, which is a relatively rare condition in which the kidneys are unable to conserve water, leading to excessive urination. When people talk about diabetes, they are usually referring to diabetes mellitus.

The food we eat provides our bodies with glucose, which is used by the cells as a source of energy. If insulin isn't available or doesn't work correctly to move glucose from the blood into cells, glucose will stay in the blood. High blood glucose levels are toxic, and cells that don't get glucose are lacking the fuel they need. These two problems cause the symptoms of diabetes.

There are two main kinds of diabetes mellitus: type 1 diabetes and type 2 diabetes. More than 90% of all people with diabetes have type 2. Overall, more than 3 million Canadians have diabetes. However, many people with diabetes are unaware they have it because its early symptoms are not noticeable without testing.

Type 1 diabetes used to be called "juvenile" diabetes, since it usually occurs in people under the age of 30. Everyone with type 1 diabetes needs to take insulin on a daily basis.

Type 2 diabetes used to be called "adult-onset" diabetes, because it usually occurs in people over 40. People with type 2 diabetes usually have a family history of this condition and most are overweight. People with type 2 diabetes are treated with a combination of lifestyle changes and medications. Some may eventually need insulin. Certain ethnic groups are at higher risk of developing type 2 diabetes. This includes but is not limited to people of Aboriginal, Hispanic, South Asian, or African descent.

Another less common form is gestational diabetes, a temporary condition that occurs during pregnancy. According to the Canadian Diabetes Association (CDA), approximately 3.7% of non-First-Nations women and up to 18% of First Nations women will develop gestational diabetes. The problem usually clears up after the baby is born, but women who have had gestational diabetes have a higher risk of developing type 2 diabetes later in life.