Diabetes involves difficulties producing insulin or using it effectively. Possible symptoms include increased thirst, frequent urination, tiredness, blurred vision and unintentional weight loss. Testing and professional assessment are needed to determine the cause. Healthy eating and regular physical activity can help prevent or delay type 2 diabetes. They do not prevent every type of diabetes. People with diabetes need individual care and monitoring for complications. This overview does not recommend medicines or interpret individual blood-sugar results. If thirst, frequent urination or unexplained weight loss develops, arrange assessment at a health facility rather than diagnosing yourself. Ask what the test measures and how you will receive results. Bring a medicine list and relevant family history. Type 2 risk reduction is different from preventing type 1 diabetes. Testing decisions and interpretation belong with your healthcare team.