Drinking large amounts of water can be a sign of diabetes, but it's by no means the only possible cause.
Many other conditions can cause excessive thirst and/or urination
, and some healthy people drink large amounts of water out of habit.
When people have uncontrolled diabetes, high sugar levels will overwhelm the kidneys and spill glucose into the urine. Glucose acts like a magnet for water, so pulls water out of the body rapidly. This leads to intense thirst and drinking large amounts of water to prevent dehydration
. Getting blood sugars under control corrects the situation, and stops the need to drink large amounts of water.
Another condition, diabetes insipidus
, can also lead to drinking large amounts of water. However, this disorder has nothing to do with blood sugar
, despite a similar name. It is caused by problems with the pituitary gland or the kidneys.