Think about it. When the body is deprived of water it perceives this as a threat and begins to hold onto every drop. Water is stored outside the cells and shows up in swollen feet, fingers, legs and hands. The over weight person needs more water than the thin person. Since we know that water is the key to fat metabolism, the overweight person needs more water.
Water also helps to maintain muscle tone.
Water helps rid the body of waste, and during weight loss, the body has a lot more weight to get rid of all that metabolized fat and it must be shed. Adequate water will help flush out the waste. Water is the medium for all body fluids, including blood, the lymph, digestive juices, urine and perspiration. Water balances acids, moves nutrients into the body's cells, and is a solution for holding electrolytes. The body's need for water is second only to its need for oxygen.