"By Bob Greene

What has no-calories and can help you in your weight-loss efforts? Water! I wouldn’t have made drinking at least six 8-oz glasses a day one of your daily must-goals if it weren’t so important. So, what is it about water and weight loss?

People who drink an average of 6½ cups of water each day consume 200 fewer calories a day, according to research from the University of North Carolina at Chapel Hill. Do the math: That’s a loss of about 20 pounds. Experts aren’t sure if the water itself helps quench appetite, but what is clear is that water-drinkers are healthier overall. They tend to have better eating habits and they drink less soda. Not to mention, drinking water can be distracting—you might be less likely to reach for chips if you have a tall glass of H2O in hand. In fact, many nutrition experts recommend drinking water when a craving first hits to delay—and potentially even prevent—an emotional eating binge. And it’s also a good idea to hydrate when you feel the urge to eat just to make sure you’re not confusing hunger for thirst.

But water doesn’t just help with weight loss. It’s necessary for all physiological processes, including digestion and calorie-burning. If you’re consuming more fiber-rich foods, like fruit, veggies and whole grains, drinking a lot of water can also help prevent constipation. Finally, water can help make your workouts a little easier. When you work out, your muscles actually hold on to water. If you’re not adequately hydrated, you’re preventing your muscles from operating at full capacity. You’re much more likely to feel fatigued when you’re thirsty, too. Finally, studies show that drinking water can help ward off certain cancers, like bladder and kidney cancers. Drinking regularly helps dilute toxins and flushes them from your system, thus, reducing the amount of time they’re in your body.

So, how much do you really need? I recommend having six 8-oz glasses a day, but if you’re active or live in warm climates, you may need a little more. But don't go overboard: There’s no need to gulp down 12 glasses. Having trouble fitting it in? It can help to get in the habit of drinking a glass with each meal.

And I’m often asked how to get it—do drinks like iced tea or lemonade count toward that goal? I usually tell people to try to hit this mark with plain old water. If you find that too bland or boring, you can add a squirt of lemon, lime grapefruit or even tangerine. Other zero-calorie alternatives that can help you reach this goal include herbal iced tea, carbonated water or flavor infused waters."