Approximately 55 to 65% of the body weight of an adult man comprises of water. Loss of water from body is so critical for survival of human being, that one can survive even after loss of almost all glycogen as well as fat, and half of body’s protein, but cannot survive if more than 20 to 22% of water is lost. Water is used as a building material in every cell of the body. Being a universal solvent, it carries food into the body, helps digestion, absorption of food and ensures elimination of waste products from the body. Water also helps to maintain body temperature, acts as a lubricant in the mobile parts of the body such as joints and prevents friction. A one ml. water per calorie of food, has been recommended under ordinary conditions. This means, an intake of roughly 6 to 8 glasses (1.5 to 2 litres) of water per day.

Proteins
Food That Provide Proteins
Proteins provided by various foods are given below:

Foods	Protein Content (gm per 100 gm of food)
Milk	4
Skimmed milkpowder	38
Cereals	6–12
Cheese	24
Meat/poultry/fish	18–20
Soybean	43
Pulses & legumes	18–24
Nuts & oilseed	18–25
Channa (Paneer)	15

Protein foods having high biological value
The biological value of protein indicates its quality. The biological value depends on its amount of essential amino acids content. Foods that are rich in protein for e.g. milk, fish, meat and soybean have high biological value. These are known as “First class proteins” or “Good quality proteins”. The required quantity of proteins can be maintained by providing with 75 per cent vegetable proteins together with 25 per cent animal proteins or 50 per cent cereal protein and 50 per cent protein from pulses and legumes.
Excessive intake of protein is harmful
Studies have s