Type 2 diabetes mellitus is not curable. The condition can be characterized as "in remission", but that does not mean you are cured of the disease.
T2DM is diagnosed through abnormal blood glucose tests that are indicative of two processes. First is insulin resistance, which slows the intracellular metabolism of glucose into energy. The body is less capable of using the insulin it produces, so the glucose in the blood builds up (causing hyperosmolarity as well as potential ketoacidosis) and is expelled through urine (the "sweet" diabetic urine). Secondly, the pancreas releases less insulin into the body, again hindering the body's ability to metabolize glucose. Neither of these processes is fully curable, only treatable, and both are considered chronic conditions.
Changing your diet and lifestyle to better support healthy metabolism and consumption of less foods that are broken down into glucose can allow you to function without outside support from insulin or other medications, as long as the disease has not progressed too far. Your body is still capable of some level of insulin absorption, and does still produce a reduced amount of insulin. But if you resume your previous lifestyle the disease will continue to progress. It's also worth mentioning that losing weight greatly improves circulation which aids in glucose metabolism.