Water promotes a thermogenic state, which in return increases your metabolic rate. The faster your metabolism, slower your propensity to gain weight.

But is it really water that I am talking about? No. What I am really referring to is hydration. The human body works hard at keeping a certain amount of water and salt in your tissues relative to amount of water and salt in your blood.

Proper hydration is a reflection of correct balance of water and salt that exists between your blood and surrounding tissues. Your diet should help your body sustain correct amount of water and salt in your blood and not disrupt existing balance between your blood and tissues.

Let me explain...

Water & Salt Balance

True hydration is sustaining an amount of water in your blood relative to your tissues that reflects overall water and salt balance your body works at creating. Looking at graphic, fluids that cause water to move out of your blood or into your blood are not ideally hydrating.

Salt Moves Water

For a fluid that you drink to be hydrating it should have little effect on moving water. Water will always move to environment with higher amount of salt. Looking again at three possible "tonicity" states, which one is most hydrating?

Before You Start Take Time to Look at How Body Works with Carbs:

It is true that weight that is lost starting out on low carb diet is a lot in a short period of time, but most of weight that is lost is water and carbs that are stored in your body. Carbohydrates are stored in muscles. Each gram of a carbohydrate that is stored in muscle is also stored with 3 grams of water. When you cut out carbohydrates your body uses stored carbohydrates in your muscles for fuel. As these carbs are used up water that is stored with them is taken out also, so result is weight loss at beginning of a low carb diet and some inches lost due to depletion of carbohydrate stores in your body. As carbs and water leave muscles muscles become depleted and loses volume.

Once carbs are added back into diet muscle take up these carbs along with water, so if carbs are reintroduced into diet in a couple days time initial weight that was lost will be regained.

Your brain requires carbs for energy also. The brain uses 400 calories a day just for standard thought process of staying alive. So this is 100 grams of carbs a day that is required for one body function. Any movement that you do for longer than 3 minutes requires carbs to be used for energy.