Type 2 diabetes develops when the body either does not produce enough insulin, or much more commonly, when the body develops a resistance to using insulin, called insulin resistance. With insulin resistance, enough insulin is produced, but the body is unable to use it. This leads to more insulin being produced to compensate and maintain normal glucose levels.
This situation may continue for some time, but eventually this compensation mechanism starts to become overwhelmed, especially if the condition is not treated, leading to high levels of insulin and also high levels of glucose in the blood. These high glucose levels are detectable and may cause symptoms. Type 2 diabetes is diagnosed if the fasting level of blood glucose is 7.0 mmol/l or more, or the non-fasting level is 11.1 mmol/l or more.
The symptoms to look out for are any of the following which may have changed from your usual pattern, or are unusual for you: