Drinking water benefits every cell in your body. It hydrates your skin and helps keep you alert. But can it help you to lose weight?

Women's magazines and diet gurus have long promised that if you gulp a lot of water, you'll feel full and eat less, and the pounds will melt away.

If only it were that easy. Unfortunately, that's one of the biggest diet myths out there.

In my lab at Penn State, we have found in four separate studies that drinking up to 16 ounces of water either before or during a meal did not impact food intake. The water empties too quickly from the stomach to have a significant effect on hunger.

There's also the misconception that water is an appetite suppressant. What really happens is people sometimes think they're hungry when they're actually thirsty. We get thirsty because the level of salt in our blood becomes high or because our blood volume decreases. We get hungry because we need nutrients. In reality, the body reacts to the sensations differently, but because hunger and thirst often occur around the same time — at meal times — it is possible for people to confuse them. As a result, people will snack when a few sips of water is all they need. But the water isn't staving off hunger pangs, it's quenching your thirst.

Eat your water
If you really want to lose weight with water, eat it! Foods such as fruits, vegetables and soups are mostly water. When you eat a meal with a high water content — stews, casseroles and pasta with vegetables, for example — the water adds weight and volume to the meal, but no calories. You feel like you're eating more, but you're getting fewer calories overall.

In a Penn State study, women who ate a chicken-rice casserole cooked with additional water ate about 100 fewer calories than when they were given the same casserole with no additional water cooked in, or the casserole plus a 10-ounce glass of water.

Even if drinking water won't make you skinny, you need adequate amounts of it to be healthy. It's recommended that women drink about 9 cups of fluids a day, including water and other beverages, 13 cups for men. But you need to be careful about your beverage choices. An estimated one-fifth of the daily calories consumed by Americans over the age of 2 come from beverages. Several studies point to calories from beverages as one of the causes of the nation's rising obesity and weight problems.

Water is certainly better than chugging high-calorie beverages such as soda or juices. Because sugar can affect the way the body absorbs fluid, sweetened beverages may not satisfy your thirst when consumed with a meal, so you may end up drinking even more of them, which adds to your overall calorie intake.

If plain water just doesn't do it for you, try these low-cal substitutes: