Which of the following symptoms best describes the onset of type 1 diabetes?

Increased thirst and frequent urination are classic symptoms that indicate the onset of type 1 diabetes. This condition occurs when the pancreas produces little to no insulin, leading to elevated blood glucose levels. The body's response to high glucose levels includes pulling fluid from the tissues, resulting in increased thirst (polydipsia) as the person tries to stay hydrated. Consequently, this also leads to increased urination (polyuria) as the kidneys work to eliminate the excess glucose through urine.

While increased hunger and weight loss are indeed associated with type 1 diabetes, they are often secondary symptoms that arise due to the body's inability to utilize glucose effectively, leading to the breakdown of fat and muscle for energy. Frequent headaches and irritability can occur due to fluctuating blood sugar levels, but they are less definitive indicators of type 1 diabetes compared to increased thirst and urination. Rapid weight gain and fatigue are not typical symptoms of type 1 diabetes onset; rather, weight loss is more common due to the lack of energy available from glucose. Therefore, the symptoms of increased thirst and frequent urination provide a clearer and more direct indication of the onset of type 1 diabetes.