Expert: Tanya Zilberter, PhD - 9/22/2007

Question
Hi, I'm a 28 yr old female, and I notice when I drink water with my meals, well when I urinate, I check my scale and the numbers go down. I don't drink only water at every meal, but it's mostly what I drink daily. I'm just wondering if that's simply just water weight I'm losing or it's fluid loss that my body shouldn't lose? And, is water a diuretic? Because I look either very skinny at times when I drink it, but if I eat more, my figure looks more like it should. I'm 5'3 and 112 llbs. I don't wish to lose but maintain my weight.
Thanks and have a good day!


Answer
Hello TK,

Water is the most natural diuretic! When you drink it, it dilutes the fluids inside the body resulting in decreased blood osmolality which is a sygnal for decreasing the levels of so-called antydiuretic hormon ADH to start decreased urea recycling and increase urine flow. This is what is going on when the diuresis is normal or physiological. If it is not, it's called pathological:

Physiologic water diuresis -> Normal serum osmolality
Pathologic water diuresis -> Elevated serum osmolality

See, in both cases you retain minerals and in the pathological case,their concentration is even higher.

There's one more case:  

"Solute diuresis" occurs when the urine contains substances that require a certain amount of urine flow, but this means that your body is trying to get rid of excess soluble substances, which is good for you. Generally speaking, water-mineral balance is something that your body has no problem maintaining.

Another story is water production out of protein taken in with foods or out of muscle. This can occur when there's not enough carbohydrates stored in the muscle and you are not supplying them with carb-rich foods. But this process is not as quick as the one after you drink water. The process of burning your body fat is even slower: it takes 3500 Cal. to be burnt to lose just 1 pound of body fat.

Read about body composition here:
http://tinyurl.com/2yt95g

Hope it can help,

Tanya Zilberter