Components of Food

  • The components of food provide nutrition and hence, are also termed as nutrients.
  • Different nutrients present in food are Carbohydrate, Protein, Fat, Minerals & Vitamin.
  • Simple tests help us to detect the presence of a particular nutrient or a raw ingredient in cooked food.


  • Provides energy to our body.
  • There are two types of carbohydrates: SUGAR and STARCH
  • SUGAR: it is called SIMPLE carbohydrates. Source: fruits, honey, and table sugar
  • STARCH: it is called COMPLEX carbohydrate. Plants store energy in the form of starch. Source: Rice, wheat, corn, potato, and bread.
  • If after adding iodine to the food, the food turns into blue-black colour, then it indicates that it contains starch.
  • In our digestive system sugar and starch are broken down into glucose by various enzymes (substance produced by a living organism which helps to bring about a specific biochemical reaction)
  • GLUCOSE is the SIMPLEST form of Carbohydrates.
  • It is then absorbed into the blood and provides us energy.


  • Provides energy to our body.
  • Fats are the slowest source of energy but the most energy-efficient form of food.
  • Each gram of fat supplies the body with calories, more than twice that supplied by equal amount of proteins or carbohydrates.
  • Food containing both carbohydrates and fat are called ‘ENERGY GIVING FOODS’
  • There are of two types of FAT: SATURATED and UNSATURATED.
  • SATURATED: Normally Solid at room temperature. E.g. butter and ghee.
  • UNSATURATED: Normally Liquid at room temperature. E.g., vegetable oil
  • There are generally two types of source of fat: Plant & Animal
  • Plant source: ground nut oil, Mustard oil, Sunflower oil, Coconut oil, Cashew, Soyabean
  • Animal source: Butter, ghee, milk, cheese, egg yolk, Meat, fish.
  • Excess body fat leads to a condition called Obesity. Obesity may lead to heart diseases.


  • Protein is needed for growth and repair of our body.
  • Food containing proteins are called ‘BODY BUILDING FOODS’
  • Children require more protein because of the rapid growth of their body.
  • Our Muscles, organs even bloods are made up of mostly proteins.
  • There are generally two types of source of Protein: Plant & Animal
  • Plant source: peas, soyabean, groundnut,
  • Animal source: Milk, cheese, fish, meat, chicken, eggs
  • Protein rich food → put it in test tube and add some water → heat the test tube for 1 min → let it cool, then add two drops of COPPER SULPHATE soln and SODIUM HYDROXIDE → turn PURPLE / VIOLET to confirm presence of Protein.


  • For proper functioning of our body we need vitamins in our diet.
  • Vitamins keep us healthy.
  • There are about 20 vitamins
  • Vitamins are of two types: FAT-SOLUBLE and WATER – SOLUBLE.
    1. FAT- SOLUBLE: A,D,E,K Stored in fat tissues of our body. Our body prepares vitamin D in the presence of sunlight.
    1. WATER – SOLUBLE: B1,B2,B3,B6,B12, FOLIC ACID & VITAMIN C Not stored in body, so regular intake is necessary .


  • Minerals are nutrients that contain certain elements.
  • They are required in small quantities in our diet.
  • Their deficiency also leads to efficiency diseases.
  • Minerals are of two types: MACRO-MINERALS & TRACE MINERALS
  1. MACRO: Required more in amount by our body e.g., Calcium, magnesium, Sodium, Potassium
  2. TRACE: Required in very small amounte.g., Iron, Zinc, Copper, Iodine.

Importance of Nutrients




1. Carbohydrates

Cereals, maize potatoes, sugar, honey,

banana, melon, papaya

·   Provide energy.

2. Fats

Butter, ghee, milk, cheese, oil, egg yolk, meat

·   Provide twice as much energy as compared to carbohydrates.

3. Proteins

Milk, pulses, peas, beans, chicken, fish, eggs, cheese

·   Necessary for the growth and repair of the body.

·   Protein rich foods are known as

bodybuilding food items.



Vitamin A

Carrot, milk, green leafy vegetables

·   Good eyesight

·   Healthy skin

·   Hair

Vitamin B1

Wholegrain cereals, potatoes, green vegetables

·   Growth and proper functioning of

the digestive system, heart, nerves and muscles.

Vitamin C

Citrus fruits, amla, tomato, guava

·   Healthy teeth, gums

·   Healthy joints

·   Increases the resistance of the

body to infections and helps in fighting diseases.

Vitamin D

Milk, fish, egg, butter. Some Vitamin D is also made in our body when the skin is exposed to early

morning sunlight.

·   Normal growth of bones and teeth.

·   It helps to absorb calcium from food.


Milk, pulses, green leafy vegetables, seafood, salt (iodine), fruits, etc.

·   Proper functioning of the body.

·   Formation of blood

·   Coagulation of blood

·   Functioning of muscles

·   Functioning of nerves, thyroid gland, etc.

Dietary fibres

Plant products, whole grains, pulses, fresh fruits and vegetables

·   They are also known as roughage.

·   Help to eliminate undigested



Besides liquid water, many food items contain water, such as tomatoes, melons, cabbage and lettuce.

·   Absorbs nutrients from food.

·   Helps in transportation and regulation within the body.

Balanced Diet

  • A balanced diet contains all the classes of food in adequate proportions which supply the required energy for the body and maintain proper growth and functioning of the body.
  • The requirement of energy varies from person to person depending on age, gender, height, weight, type of occupation, lifestyle and climate.
  • Food such as pulses, groundnut, sprouted seeds, fermented foods, spinach and a combination of flours are highly nutritious.
  • Junk food refers to any food which is high in salt, fat, sugar or calories and low in nutrient content.
  • Few examples of junk food are fried snacks, aerated drinks, gum, sugar candy, most sweets and desserts.
  • Prolonged consumption of such foods can deprive the body of a balanced diet which may lead to problems such as diabetes, heart diseases and obesity.
  • Obesity is a condition where excess fat accumulates in the body.

Preventing Loss of Nutrients

  • It is important that food is cooked right so that its nutrients are not lost.
  • Vegetables and fruits must be washed before cutting. This will prevent loss of nutrients.
  • If vegetables have to be peeled, then the peels must be as thin as possible to prevent the loss of nutrients.
  • Repeated washing of rice and pulses may remove water-soluble vitamins.
  • Many nutrients and minerals are lost when excess water used for cooking is thrown away. Overcooking of food must be avoided.

Deficiency Disease

Deficiency of one or more nutrients can cause imbalance or disorders in the body.

Diseases which occur due to lack of nutrients over a long period are called deficiency diseases.


Diseases caused by its



Vitamin A

Loss of vision

Poor vision, loss of vision in darkness or sometimes

complete loss of vision

Vitamin B1

Beriberi, pellagra, etc.

Weak muscles and very little energy to work

Vitamin C


Bleeding gums and wounds which take time to heal

Vitamin D


Bones become soft and bent


Osteoporosis, tooth decay

Weak bones and tooth decay



Glands in the neck appear swollen





Kwashiorkor in children

The stomach swells and bulges with swelling of feet.

The child has stunted growth and reduced immunity.


and Proteins


The child becomes thin. Bones can be seen through

the skin; ribs can be clearly seen.

Different Type of Food

Energy-giving food

Carbohydrates and Fats. Carbohydrates provide us instant energy. Fats are stored energy resources

Body-building food

Proteins are body-building food as they help in body growth and repair of damaged parts of the body.

Protective food

Vitamins and minerals are protective food as they protect us from many diseases. They give us resistance against disease causing germ

Roughage or dietary fibers.

  • Roughage is the fibrous matter in food which can’t be digested.
  • Mainly made of an indigestible carbohydrate called ‘cellilose’ which is present in plant cell walls.
  • It does not provide any nutrient to our body.
  • It has no FOOD VALUE but its presence is essential in our food.
  • Lack of fibers in our diet causes the stool to become hard & difficult to pass. This condition is called constipation.


  • Water makes up almost 70 per cent of our body weight.
  • It helps to transport substances inside our body.
  • It helps our body to absorb nutrients from food.
  • It helps to regulate our body temperature.
  • It is needed for various chemical reactions that take place inside our body during digestion, excretion, etc.
  • We get water not only from the liquids we drink but also from the food we eat. Milk, fruits, vegetables, and juices are good sources of water.