Food is one of the basic needs of all living beings. Plants and animals are the main sources of food. Food can be eaten in cooked and uncooked forms. Uncooked foods are known as raw foods. The food gets soft and tasty when we cook. Also cooked food can be easily digested.

Rice and pulses are examples of cooked food whereas fruits and milk are examples of raw food.                                                                    

Why do we need food?

  • Food gives us energy.
  • Food helps us to maintain good health.
  • Food helps us to grow.
  • Food develops immunity against diseases.

Science Class 3 Food  

Science Class 3 Food

Nutrients and Balanced Diet

Healthy substances present in the food are called nutrients. The different types of nutrients are 

Science Class 3 Food

  • Carbohydrates – energy producers

 We need energy to grow, to work and also for our different body organs to work. The foods which give energy are called 'Carbohydrates'. For eg: ragi, maize, jowar, bajra etc

  • Proteins - body builders

They help in growth. For eg: grams, peas and pulses. Always some cells die and are replaced by new cells in our body. When we get injured new cells are formed to heal the wound. Nutrients called 'Proteins" are essential to heal the wound. These proteins are found in pulses (dals). Apart from proteins, pulses also contain starch, vitamins and mineral salts in minute quantities. In foods like fish, eggs, meat and milk abundant proteins are available. Milk contains calcium which helps in the growth and strengthening of bones. Hence, we should see that the food which we are taking includes pulses, milk and eggs.

  • Vitamins and Minerals - body regulators

 Vitamins are necessary to make use of the carbohydrates and proteins eaten by us. Mineral salts like iodine, phosphorus, calcium, iron combine with proteins and form a part of our organs. Iron is found in the blood, calcium, phosphorus are present in bones and teeth. Vitamins are found in sprouts (germinating seeds) and also the food items soaked over night in water (idli, dosa....) vitamins and mineral salts are necessary for our body and are found abundantly in fruits and vegetables.

Science Class 3 Food

The food consumed by us should have correct proportions of nutrients according to our age and work. A balance diet is a diet that contains adequate amounts of carbohydrates, fats, proteins, vitamins and minerals.

Food Spoilage

Science Class 3 Food  

All food items get spoilt over a period of time. We know that the food is spoilt if there is a bad smell coming from food and if there is a bacteria growth on food. Food will be spoiled if it is not prepared, preserved and handled in the correct way.

Preserved foods

Let us see whether the spoilage of food can be prevented. There are measures that can be taken to prevent the growth of fungi and bacteria which cause the food to spoil.

  • By refrigerating food - At low temperature bacteria and fungi do not grow.
  • By preserving - Using of various preservation techniques prevent the growth of bacteria.

 All fruits and vegetables are not available during all seasons.  Fruits and vegetables will remain fresh for a longer period of time if preserved.  Preserved food can be transported to distant places without spoilage. 

Junk Foods and Food Wastage 

Science Class 3 Food

We do not get the required nutrients by eating such junk foods. Generally, junk foods fried foods contain only calories (carbohydrates) rather salt and oil they cause harm to our body. So, it is better to avoid them, than become fat by eating such foods. This problem is faced by people all over the world.

If excess food is cooked then it gets wasted. Left over food is thrown as waste. Some people spill the food while eating and some waste the food without eating completely. Food grains like rice, wheat, pulses like grams and oilseeds like ground nut are attacked by insects and fungi, causing decay and damage to them. Hence to avoid this, neem leaves are placed in the storage bags and huge bins. Rats also spoil the stored food grains. Ants make the sugar and jaggery unusable.


Science Class 3 Food