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.
Importance of Water. Water is used for various important purposes: Water in Agriculture. Water plays the most important role in agriculture. Agriculture is impossible without irrigation throughout the crop season. Irrigation ensures proper plant growth.
Nutritional Value of Water. Adequate water intake is vital for good nutrition. Water is a nutrient all its own, helping every cell in your body function properly. Most people get about 20 percent of their water through food and the rest by drinking water or other beverages.