The typical consumer has many misconceptions about the role water plays in body weight. In part these faulty ideas have been promoted by over-the-counter products designed to rapidly reduce weight, or the bloating many women experience just before their period begins. In actuality, the more water you drink (within reason), the less likely your body is to retain water. Drinking too little water tells the body that a drought may be imminent; hence it holds onto as much water as it can by concentrating your urine, and reabsorbing as much water as possible from feces prior to defecation. Drinking sufficient water allows your body to flush toxins from your tissues and free itself of excess water.

Both beverages and food provide your body with water. Regardless of their other constituents all beverages are primarily water. Most foods also provide water. Fruits and vegetables are obvious sources. Water is available from less apparent sources also, such as pasta, rice, and oatmeal, which absorb water while cooking.

Despite the numerous potential sources of water in your diet pure water is still the best source of dietary water. Most of us can remember having drunk a soda, juice or coffee and still feeling thirsty. These beverages add fluid to the body but they also add solutes (sugar, salt, and various chemicals) that must be diluted as they enter the blood stream. Your body dilutes these solutes by pulling fluid from your cells into your bloodstream.

Caffeine- and alcohol-containing beverages present your body with another type of challenge. In addition to any solutes, these beverages contain caffeine and alcohol, which dehydrates your body by affecting the hormones that regulate your body's fluid balance. Your body responds by producing extra urine. So that cup of coffee you have in the morning may take more body fluid with it than it supplies.

At the very least, people need a little over a quart of water each day just to replenish the amount lost in urine, feces, sweat, and from the lungs during respiration. Two quarts per day is optimal intake under average conditions but this amount can increase in very warm weather, during intense prolonged exercise, and by various physiological changes brought about by disease, medications or even natural physiological alternations such as pregnancy and lactation.

Providing you do not drink a lot of caffeine- or alcohol-containing beverages, the best way to tell if you are drinking enough water is by the color of your urine. It should be pale yellow at least once a day.