Hi winglets and welcome to the Diabetes Forum! Well, remember that no one is a doctor here but I will try to answer your questions as best I can.
I don't think if a person drinks one litre of water or any liquid that exactly one litre is expelled as urine. We also release sweat through our pores, moisture in our breath and our bodies' cells and organs use water for function so even though those amounts are small, if you measure intake and output, it's hard to says what's being used and what's being retained in the body.
Coffee and tea can act as diuretics and make a person need to urinate. And that would not only be from what they drink but from the body cells that retain liquid.
A person who has uncontrolled high blood sugar will urinate more according to what I've read no matter the amount of liquid they drink. The kidneys try to get the glucose out of the blood stream and they try to gather up water in the body to flush it out.
If a person is urinating more than usual, then it's best to have some lab work done with blood and urine tests for the blood glucose and kidney function. Only that can tell you what's going on with this.
If a person has diabetes in his family and is overweight, then he needs to see his doctor and get these tests done sooner rather than later.
Do you have any family members who are diabetic?
Laniediabetes moderatordiabetes type 2 controlled by diet and exercise and
very low carb way of eating Check out the following site for more info on blood sugar:www.phlaunt.com/diabetes/