Components of Food

Food : It is the group of edible substances which provide energy to the living beings and repairs the old tissues and builds the new tissue.

2.   Nutrients :The components of food that are necessary for growth, maintenance and other activities are called nutrients.

Nutrition :The process of taking nutrients required for growth and development of our body to obtain energy is known as nutrition.

Our food contains three main substances called nutrients. These are fats, proteins and carbohydrates. In addition our body requires water, salts (minerals), vitamins and fibres.

Diet : It is the amount of food taken by a person at a time.

Balanced diet :A diet containing all the nutrients and other components in proper proportion is called balanced diet.

Energy :Energy is capacity to do work.

Malnutrition :If a person does not get adequate food, or if his/her diet does not contain all the nutrients, he or she becomes weak. When the body does not get adequate nutrition, it is said to be suffering from malnutrition.

Various food components are grouped in three classes :
Energy giving foods : Carbohydrates and Fats.
          (ii)      Body building foods :Proteins.
          (iii)    Protective foods :Vitamins and Minerals.

(i)            Grains such as rice, wheat, sorghum, peas, beans, sago (sabudana), sugarcane, sugarbeets, many fruits like banana, mango and melons and vegetables are good sources of carbohydrates (Fig. 2.1).
(ii)          Cellulose, starch, sucrose, glucose and fructose are the important carbohydrates found in our food.
(iii)         Starch turns iodine solution to dark blue or black.

(i)            Fats are obtained either from animals or from plants. Fats like butter and ghee are obtained from animals. Groundnut oil, Soyabean oil and Mustard oil are examples of fats derived from plants.
(ii)          Facts act as fuels in our body but they provide more energy than carbohydrates.
(iii)         Our body has some advantages of fat deposits in small quantity. It helps body organs and protects them from injury, prevents loss heat from the body surface.
(iv)         Too much fat deposition is harmful for the body. This leads to the condition called obesity.
(v)          Fatty substances leave greasy and transparent spot on paper.

12.               Proteins

(i)          Milk, fish, meat, cheese and eggs are the main sources of animal proteins. Vegetable proteins can be obtained from legumes including pulses and beans.
(ii)         Proteins are required for growth and repairing in our body. They help in building new tissues. They also account for tough, fibrous nature of hair and nails and for the structure of muscles. They are a part of our blood and help in proper functioning of our body.
(iii)        Large amount of protein is needed for building new tissue in short period, such as during infancy, pregnancy or when mother is nourishing a child.
13.               Vitamins : Vitamins are required by our body in very small quantities. Vitamins help in keeping our eyes, bones, teeth and gums healthy. The food items rich in vitamins are called protective foods as they protect our body from diseases and keep us healthy.
14.               Minerals : Minerals are needed by our body in small amounts. Each one is essential for proper growth of body and to maintain good health.

15.               Different sources of vitamins and minerals are shown in Figs. 2.4 and 2.5 respectively.
16.               Water

(i)          Our body requires a large quantity (5-7 litre) of water daily.
(ii)         Water helps our body to do many functions like digestion, throwing our dissolved waste from body as urine and impure blood.
(iii)        Water also keeps our body cool through sweating.
(iv)       Water helps in blood circulation.


(i)          Whole grains flour and cereal, potatoes, fresh fruits and raw and cooked vegetables provide roughage in our food.
(ii)         It helps in proper digestion and prevents constipation.

Foods that are deep fried and roasted usually loose their nutritive value.

Energy requirement : Requirement of energy or food depends on profession, age, sex and special needs like pregnancy, infancy, lactation, etc.

Deficiency diseases : Diseases that occur due to the lack of nutrients are called deficiency diseases. Some of them are listed in the following table :

Table 2.1. Some diseases or disorders caused by deficiency

of vitamins and minerals
Name of Vitamins/
and minerals
Disease or Disorder
Main Symptoms
Vitamin ANight blindnessPoor or loss of vision in darkness (night), sometimes complete loss of vision
Vitamin B1Beri-beriWeak muscles and very little energy to work
Vitamin CScurvyBleeding gums
Vitamin DRicketsBones become soft and bent
IodineGoiterGlands in the neck appear swollen, mental disability in children
21.               Beri-beri : It is a disease caused due to the deficiency of Vitamin B1. In the victim of beriberi muscles get weak.

Scurvy : Scurvy is caused due to the deficiency of Vitamin C. Bleeding gums are main symptom.

Q.1. Name the major nutrients in our food.

Carbohydrates, fats, proteins, vitamins, minerals, roughage and water are essential nutrients for our body.

Q.2. Name the following :

a)  The nutrients which mainly give energy to our body.
b)  The nutrients that are needed for the growth and maintenance of our body.
c)  A vitamin required for maintaining good eyesight.
d)  A mineral that is required for keeping our bones healthy.


a)   Carbohydrates and fats
b)   Proteins
c)   Vitamin A
d)   Calcium

Q.3. Name two foods each rich in :



Dietary fibre



a)   Fats : Butter, ghee, cheese, groundnut.

b)   Starch :Rice, wheat, bajara.

c)   Dietary fibre :Spinach, cabbage, ladyfinger, sprouted grains, papaya.

d)   Protein :Milk, meat, fish, egg.

Q.4. Tick (v) the statements that are correct :

By eating rice alone, we can fulfill nutritional requirement of our body. (  )
b)  Deficiency diseases can be prevented by eating a balanced diet. (  )
c)  Balanced diet for the body should contain a variety of food items. (  )
d)  Meat alone is sufficient to provide all nutrients to the body. (  )


a)   Incorrect ( x )
b)   Correct ( v )
c)   Correct ( v )
d)   Incorrect ( x )

Q.5. Fill in the blanks :

a)  ………….. is caused by deficiency of vitamin D.
b)  Deficiency of ………….. causes a disease known as Beri-beri.
c)  Deficiency of vitamin C causes a disease known as ……….. .
d)  Night blindness is caused due to deficiency of ………… in our food.


a)   Rickets
b)   vitamin B1
c)   Scurvy
d)   vitamin A

                                                                                                                    ADDITIONAL IMPORTANT QUESTIONS

Q.1. Name any two sources of Vitamin B.

Ans. Milk and soyabean.

Q.2. Name the vitamin present in orange.

Vitamin C.

Q.3. Write the names of fat soluble vitamins.

Vitamin A and Vitamin D.

Q.4. Write the names of any two water soluble vitamins.

Vitamin B and Vitamin C.

Q.5. Name the disease caused by deficiency of Vitamin A.

Night blindness.

Q.6. What are the sources of carbohydrates ?

Rice, wheat, maize, potatoes, sugar and jiggery are the sources of carbohydrates.

Q.7. What are enzymes ?

Enzymes are the proteins which help in reactions taking place in the body.

Q.8. Name the main constituent of roughage.

Cellulose is the main constituent of roughage.

Q.9. Our bones and teeth are made of which minerals.

Calcium and Phosphourus.

Q.10. Which among the following provide maximum roughage to the diet if taken in equal amount  ?

            egg, cucumber, grapes, cabbage

Ans. Cabbage.

Q.11. What are nutrients ?

Ans. The food we eat gives us energy to live. Food contains substances that are useful to our body. These are called nutrients.

Q.12. What are essential nutrients for our body ?

Carbohydrates, fats, proteins, vitamins, minerals, roughage and water are essential nutrients for our body.

Q.13. What is nutrition ?

The process of taking nutrients for the growth and development of body and to obtain energy is known as nutrition.

Q.14. Write the functions of food.

Our food provide us energy for proper growth, to give protection against diseases and to carry out physical work.

Q.15. What is a balanced diet ?

A diet in which every component of food (carbohydrate, fat, protein, vitamins, minerals etc.) is present in proper amount is known as balanced diet.

Q.16. What do you mean by staple food ?

The main food that we eat to provide us energy is called staple food. In our country rice, chapatti and bread are staple food.

Q.17. What is the role of Vitamin C ?

Vitamin C helps in proper growth, healthy teeth, gums and joints and keep the body fit and to fight against the diseases.

Q.18. What is the function of vitamins ?

Vitamins only help in the proper utilization of other nutrients such as carbohydrats and fats. Many vitamins help enzymes in their action and are called co-enzymes.

Q.19. What are symptoms of Vitamin C ?

Gums begins to crack and bleed. Wounds on skin take longer time to heel.

Q.20. Write the sources of fat.

Fats are found in vegetable oils, ghee and butter, milk, cheese, meat, fish and codliver oil, etc.

Q.21. How will you test for fat in a sample ?

Put that sample on a piece of paper and crush. If the paper at that spot becomes translucent and greasy, the sample contains fat.

Q.22. Which one gives you more energy – one banana or 100 grams of grapes ?

One banana gives 104 calories of energy while 100 grams of grapes give only 17 calories. Hence one banana gives more energy.

Q.23. What are the sources each of animal and vegetable protein ?

(i)Sources of animal proteins : egg, meat, fish, milk.
         (ii)Sources of vegetable proteins : pulses, peas, bean, soyabean.

Q.24. What is haemoglobin ?

Blood contains a very important protein called haemoglobin. It transports oxygen from the lungs to body cells.

Q.25. Tell your mother why should she not sieve wheat flour before making dough.

During sieving the roughage part of flour is sieved out and eating such floor for many days constipation develop.

Q.26. What is dehydration ?

If a person looses large quantities of water from the body, many nutrients dissolved in it are also lost. This condition is called dehydration. We feel weak because of it.

Q.27. What is ORS ? How does it help us ?

ORS is the short name of Oral Rehydration Solution. It helps us in making up water and mineral lost from the body because of dehydration.

Q.28. Name the different food groups.

Food can be broadly sub-divided into following three groups :

(i)          energy giving foods. For example, carbohydrates and fats.
(ii)         body building foods. For example, proteins.
(iii)        protective foods. For example, vitamins and minerals.

Q.29. (a) How many calories does a 12 year old boy/girl need each day ?

          (b) How can this boy/girl get this in the diet ?

(a) A 12 year old boy/girl needs 2000-2200 calories per day.
         (b) He can get this by a diet including daal, rice, roti green vegetables and a bit of jiggery.

Q.30. Why fat is considered more energy yielding than carbohydrates ?

Fats yield more energy because they contain a higher percentage of carbon and hydrogen element which produce energy on oxidation and low percentage of oxygen which does not produce energy.

Q.31. How can you balance your diet without adding to its cost ? Suggest any one method to do so.

The idea that something is costlier and harder to get should be more valuable as a food is called food-fad. People think that grapes are more nutritious than banana and spinach. It is a food fad and it is only because grapes are costlier than banana and spinach.

Q.32. Name some practices of food preparation which lead to loss of nutrient value ?

Washing of peeled vegetables and some fruits may remove the water soluble vitamins. Heating of food materials during their cooking may destroy some of the vitamins and also change the property of some nutrients like protein to varying degree.

Q.33. Which has more vitamins – 100 grams of spinach or 100 grams of grapes ?

Spinach has more vitamins than grapes. 100 gm spinach contain 3 mg of vitamin A, 30 mg of vitamin C, while 100 gms of grapes contain no Vitamin A or B but 1 mg of Vitamin C.

Q.34. Why it is advised to take iodised salt ?

Iodised salt contains iodine. Iodine deficiency results in the enlargement of thyroid gland, retarded growth and mental disability. Iodized salts helps us to overcome iodine deficiency.

Q.35. Write three important properties of a balanced diet.

A balanced diet has following properties :
(i)          It is rich in essential nutrients such as vitamins, minerals and certain amino acids.
(ii)         It provides just enough raw material to take care of the needs of growth, repair and replacement of cells, tissues and organs in the body.
(iii)        It provides energy required for the body.

Q.36. What steps should we take to overcome the condition of dehydration ?

In case of dehydration, we should :
(i)          Drink as much water as possible.
(ii)         Take drinks available at home like  soup, jaljeera etc.
(iii)        Take ORS (Oral Rehydration Solution).

Q.37. Why does a teenager need more food than a baby ?

A balanced diet contains different food material. The component of a balanced diet differ according to age, sex and physical activity of an individual. We know that a teenager does the different activity like eating, sitting idle, talking, sleeping, writing, cooking etc. So more energy is required for these activities. That’s why teenager need more food than a baby.

Q.38. What are protective foods ? Give examples.

Ans. Vitamins and minerals help in protection of body against diseases and hence they are also known as protective foods. Green vegetables and fresh fruits contain vitamins and minerals. Some proteins also protect us from the infection of microorganism. The protein could be available from two sources vegetables and animals. Milk, fish, meat, and egg are the main sources of animal proteins.
Q.39. Why does our body need nutritious food ?

Ans. We know that food is needed for the growth of our body. Food gives us energy to work and play. It gives us resistance against diseases. The components of food are carbohydrates, proteins, fats, vitamins, minerals, fibre and water. Nutrients are the components of food that the body needs in adequate amounts for growth, to reproduce and to lead a normal healthy life. All types of nutrients have their own functions to perform, but the different nutrients must act together. So nutritious food provide energy for all the activity of body.

Q.40. What is malnutrition ? What are its harmful effects ?

Malnutrition is the physical state of a person resulting either from a faulty diet or from physical inability to absorb nutrients properly due to some disease.
The harmful effects of malnutrition are :
(i)          Deficiency of any of the nutrients in our diet causes diseases.
(ii)         Deficiency of protein causes kwashiorkor disease.
(iii)        Deficiency of carbohydrate, protein, fat causes Marasmus.

Q.41. What is the effect of protein deficiency on the health of children ?

If a child does not get enough protein in his food for long time, he is likely to suffer from protein deficiency. Children suffering from protein deficiency have light brown hair, face like that of an old man, always hungry, they have distended stomach. They are under weight and skinny with very little flesh on bones. This disease is called Kwashirkor.
Q.42. What is roughage ? Why its presence in our food is important ?

The rough, fibrous content of food is called roughage. Green vegetables like spinach, cabbage, ladies finger and beans contain a good amount of roughage.

Role :
Roughage helps in the movement of bowl. This prevents constipation.

Q.43. Name the foods each rich in :

(i)dietary fibre
(ii)              sugar
(iii)            protein
(iv)             starch
(v)               fats and oil.


(i)  Dietary fibre : Spinach, cabbage, ladies finger.
(ii)Sugar : Milk, banana, sugar cane.
(iii)                Protein : Milk, meat, fish, egg.
(iv)               Starch : Rice, wheat, bajara.
(v)Fats and oil : Butter, ghee, cheese, groundnut.

Q.44. Name the foods needed :

for strong bones and teeth
(ii)              to prevent scurvy
(iii)            to avoid constipution
(iv)             for warmth
(v)               for growth


(i)  The bones and teeth are made up of salts of calcium and phosphorus. Calcium is found in milk, buttermilk, cheese, green leaf vegetables, ragi. While cereals, pulses, fish and meat is good sources of phosphorus.
(ii)To prevent scurvy, vitamin C is required, which is found in citrus fruits, green and red peppers.
(iii)                To avoid constipation roughage is very important. Roughage is mostly given by the foods derived from plants, which contain enough cellulose. Mostly vegetable, fruits, and whole grain provide roughage in our food.
(iv)               For warmth : ghee, butter, meat and fish etc.
(v)For growth : milk, green leafy vegetables.

Q.45. What are various functions of protein ?

Functions of protein are :
(i)  Proteins are the building materials of our body.
(ii)Proteins are the constituents of enzymes.
(iii)                Proteins make our muscles, skin, hair and nails.
(iv)               Protein forms a red pigment in blood which acts as oxygen carrier.
(v)Proteins like fibrin help in clotting of blood.
(vi)               Proteins help in repairing damaged, replacing wornout or dead cells and tissues.
(vii)Proteins help to develop resistance of the body against various infections.

Q.46. What are the roles of (a) Carbohydrates (b) Fats (c) Proteins (d) Vitamins

(e) Minerals.


a)  Role of carbohydrates : Carbohydrates provide us energy.
b)  Role of fats : Fats provide us energy.
c)  Role of proteins :
(i)  Proteins help in digestion.
(ii)Proteins are required for building body parts.
(iii)                Proteins help in growth of muscles and whole body.
d)  Role of vitamins :
(i)  Vitamins are necessary for various physiological activities.
(ii)Vitamins keep us healthy and protect us from many diseases.
(iii)                Vitamins are required for the proper functioning of body parts.
e)  Role of minerals :
(i)  Minerals help us to make our bones and teeth strong.
(ii)They help to prepare blood.

Q.47. What is the main difference between vitamins and minerals ?


1.   Vitamins are complex molecules
Required by the body in small
2.   Some vitamins are called co-enzymes as they help enzymes to do their work.
3.   Vitamin are organic compound.
4.   They do not act as energy carrier.
1.   Mineral are elements like  phosphors, sulphur, nitrogen, chlorine, iodine, and metals like sodium, potassium, etc. this are also  required in small amounts.
2.   Some minerals also help enzymes to do their work.
3.    Minerals are of inorganic nature and are found in soil and earth crust .
4.   Mineral like phosphors act as carriers.   
Q.48. Write the sources and deficiency diseases of the vitamins ‘A’, ‘B’ complex, C, D, E and K.
VitaminsSourcesDeficiency Diseases
1.   Vitamin AMilk, butter, yellow fruits and vegetables, egg yolk, liver oils of fish.Xerophthalmia, Night blindness
2.   Vitamin B
Milk, egg, green, vegetables, cheese, meat, germinating seeds, yeast and unpolished rice.Beri-beri
3.   Vitamin CCitrus fruits, green and red peppers.Scurvy
4.   Vitamin DMilk, egg, fish, liver oil, sun light.Rickets
5.   Vitamin EVegetable seeds, eggs, sweet potato, oils, meat, sprouted grains.Sterility
6.   Vitamin KEgg yolk, liver, cheese, tomato, cabbage, soyabean, cauliflower.Improper coagulation of blood.
Q.49. Explain why you should :

eat less cakes and ice-cream.
(ii)              remove most of the fat from meat.
(iii)            eat fresh food instead of processed food.
(iv)             eat more fruits and vegetables.


(i)        Eat less cakes and ice-cream : Cakes and ice-cream contains lots of sugar and fat. Sugar and fats are energy giving food. But the amount of energy a person needs depend on a person’s age, sex and daily activities. If a person takes in more calories than are used up, the excess energy gets stored in the body as fat which leads to obesity, atheroma and diabetes.
(ii)      Remove most of the fat from meat : Animal fat contain saturated fat. Our diet should contain less of saturated fat because saturated fat easily changes into cholesterol which causes arteriosclerosis (thickening of walls of arteries) high blood pressure and heart disorder. Hence, we should try to remove most of the fat from meat.
(iii)    Eat fresh food instead of processed food : We should eat fresh food instead of processed food because during processing many of the essential vitamins and minerals are destroyed.
(iv)     Eat more fruits and vegetables : Fruits and vegetables contain many vitamins and minerals which are needed in our body. Moreover, fruits and vegetables contain cellulose which our body cannot digest. This undigestable fibre helps in bowl movement. So, we should eat more fruits and vegetables.

Q.50. Here are three strips. You have to paste them in figure at three places 1, 2 and 3. At which place you will paste each strip ?

Protein rich food
 (b)        Carbohydrate rich food
 (c)        Fat rich food
Ans. Names of strips and their appropriate places are :

Name of StripAppropriate Place
(a)Protein rich food
(b)Carbohydrate rich food
(c)Fat rich food
Place (1)
Place (2)
Place (3)


Q.1. Match the following items given in Column A with that in Column B

Column AColumn B
(a)               Energy giving food
(b)               Body building food
(c)               Protective food
(d)               Test for fats
(e)               Test for starch
(f)                Test for protein
(i)        Vitamins and minerals
(ii)      Iodine
(iii)    Fats, carbohydrates
(iv)     Copper sulphate and caustic soda
(v)       Oily patch on paper sheet
(vi)     Proteins
Q.2. Fill in the blanks with appropriate words :

For proper …………… and …………. our bodies need adequate food.
(ii)        Proteins build ………… material.
(iii)      Non-living machines burn the fuel at ………… temperature while living machines burn their food at …………. Temperature.
(iv)       Starch is a ………… of sugar.
(v)         ………….. gives blue colour with iodine.
(vi)        Proteins are made up of …………. .
(vii)     Skin, hair and nails are …………. .
(viii)   Co-enzymes are nothing but …………. .
(ix)       Vitamin C causes …………. When found deficient.
(x)         Our body contains ………… of water.
(xi)       Most of the reactions in our body occur in ………….. solutions.
(xii)     Balanced diet is one containing all ………….. .
(xiii)   An average person should drink ………… glasses of water daily.
(xiv)   Deficiency of ………… causes rough skin, weak eyesight and thinness of body.
(xv)     Excess intake of ……….. over a large period may damage kidneys.
(xvi)   Lack of …………. Leads to lethargy, inactivity and feeling of tiredness.
(xvii)Intake of inadequate quantities of proteins may ………… the growth and development of children.

Q.3. State whether the statements given below are True or False :

(i)        Deficiency of vitamin A makes our bones weak.
(ii)                      Deficiency of iron causes paleness.
(iii)                    Calcium is necessary for strong bones and teeth.
(iv)                     Deficiency of vitamin B helps to increase our appetite.
(v)                       Deficiency of vitamin D causes swollen and bleeding gums.
(vi)                     Carbohydrates are the main source of energy in our diet.
(vii)      Expensive food is not always the best food.
(viii)    Protein is a staple food.
(ix)               Haemoglobin is a carbohydrates.
(x)                 Cotton and paper are carbohydrates.
(xi)               Tomatoes contain vitamin C.
(xii)       Eating ladies finger makes you good in mathematics.

Q.4. Choose the correct option in the following questions :

(i)The food components needed by our body are called
(a)ingredients                             (b)nutrients
(c)fragments                    (d)ornaments
(ii)        Carbohydrates can be tested by using
(a)iodine                          (b)caustic soda
(c)copper sulphate             (d)fehling solution
(iii)      Which one of the following is an energy giving component ?
(a)Protein                         (b)Vitamins and minerals
(c)Roughage                     (d)Carbohydrates and fats
(iv)       Vitamins and minerals are
(a)protective foods            (b)energy giving foods
(c)body building foods        (d)roughage
(v)         Roughage helps in
(a)protecting our body from diseases
(b)movement of bowl
(c)providing energy
(d)building and repair of various body parts
(vi)       Scurvy is caused due to the deficiency of
(a)vitamin A                     (b)vitamin B
(c)vitamin C                     (d)vitamin D
(vii)      Diseases caused due to the deficiency of vitamins are known as
(a)dietery diseases          (b)cronic diseases
(c)deficiency diseases      (d)transmitted diseases
(viii)                                                                     All the deficiency diseases can be prevented by
(a)cleanliness                  (b)taking medicine at proper time
(c)vaccination                 (d)taking balanced diet
(ix)                                                                         Which of the following food items contains carbohydrates ?
(a)rice                             (b)gram
(c)cabbage                       (d)pulses
(x)Night blindness is caused due to deficiency of
(a)vitamin A                     (b)vitamin B
(c)vitamin C                     (d)vitamin D

Q.1. Match the items under Column A with Column B.

Column AColumn B
(a)               Energy giving food
(b)               Body building food
(c)               Protective food
(d)               Test for fats
(e)               Test for starch
(f)                Test for protein
(iii)Fats, carbohydrates
(i)Vitamins and minerals
(v)Oily patch on paper sheet
       (iv)Copper sulphate and caustic
Q.2. Fill in the blanks :
       (i)growth, maintenance         (ii)body                          (iii)high, low
     (iv)polymer                  (v)Starch               (vi)amino acids
     (vii)proteins                  (viii)proteins           (ix)scurvy
     (x)67%                        (xi)water                (xii)nutrients
     (xiii)eight                     (xiv)proteins           (xv)carbohydrates
     (xvi)fats                       (xvii)slow down
Q.3. True/False :
     (i)False               (ii)True           (iii)True            (iv)False         (v)False
       (vi)True              (vii)True          (viii)False         (ix)False         (x)True
       (xi)True              (xii)False
Q.4. Choose the correct option :
(i)       (b) The ingredients of food have some components which are needed by our body. Such components are called nutrients.
(ii)      (a) Carbohydrates (starch) give violet on black colour with iodine solution.
(iii)    (d) Carbohydrates and fats are main sources of energy.
(iv)    (a) Vitamins and minerals protect our body from various diseases.
(v)     (b) Roughage are rich in fibres. Fibres keep in bowl movement.
(vi)    (c) Deficiency of vitamin C causes scurvy.
(vii)  (c) Since such diseases are caused by deficiency of food components.
(viii)(d) If we take balanced diet there will not be any kind of deficiency.
(ix)    (a) Rice is a source of carbohydrates.
(x)     (a) Night blindness, unable to see in dim light or at night, night blindness is caused due to deficiency of vitamin A.