In general, foods are made up of carbohydrates, proteins, and fats, each of which provide a different number of calories: 1  Carbohydrates provide 4 calories per gram. 2  Proteins provide 4 calories per gram. 3  Fats provide 9 calories per gram.
You need water to digest your food and get rid of waste, too. Water is needed for digestive juices, urine (pee), and poop. And you can bet that water is the main ingredient in perspiration, also called sweat. Besides being an important part of the fluids in your body, water is needed by each cell to function normally. Your body doesn't get water only from drinking water. Any fluid you drink will contain water, but water and milk are the best choices. Lots of foods contain water, too.
Now lets take a closer look at the importance of water in our own bodies. As babies we are approximately 75 to 80% water and as we grow older this percentage decreases until the percentage is reduced to approximately 60 to 65% for men and 50 to 60% for women. The human brain is about 85% water and our bones are between 10 to 15% water. The chemical structure of water H 2 O and both the hydrogen and oxygen have great importance as life giving properties and a preserving force to our systems. Women have a higher percentage of adipose tissue than men, giving them a lower percentage of water.