The regular person in America, who does not exercise at all or that rigorously, needs water to lose weight. If the body does not receive adequate amounts (1-2 quarts a day), you will actually start to retain water causing a net gain in weight and the liver to cease metabolizing fat at a normal rate. Basically, your metabolism will slow to a point where fat and water is now being store by the body UNTIL it receives the proper amounts of water. An easy equation with the elements of weight loss is:
Water + Oxygen = Weight loss
Drinking water plus physical activity where you breathe at a higher heart rate (ie aerobic activity like walking, jogging, swimming, biking, resistance training etc.) will ultimately lead to weight loss. Not only will you release retained water - ending the bloated and puffy feeling, but your metabolism will burn fat at a higher rate than before you started adding sufficient water intake to your diet. If you are significantly overweight (50-100lbs), you need to add more water to your diet than the minimum recommended daily amount. Some experts agree that the intake should be another 6-8 oz. of water for every 10-20 lbs overweight.
The bad news is that coffee, tea, diet drinks, alcohol, and nicotine are diuretics meaning they actually will dehydrate you. These drinks should not count as your 1-2 quarts a day of daily water consumption. If you think you maybe retaining water, try adding up to a gallon of water a day and you could lose about five to ten pounds of retained water in a few short days.