I think you are misinformed about Type 1 diabetes. Maybe you are thinking of some other condition?
In Type 1 diabetes, the pancreas stops producing any insulin. Insulin must be administered regularly (always, not usually) or the person will die. "Other medications" aren't required.
One's diet and exercise are relevant to Type 1 diabetes treatment, but are not a treatment method.
Source: my daughter has Type 1 diabetes