Question

our diet must contain sufficient quantities of different components of food give reasons for the following

Answer 1

1.   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.

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

4.   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.

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

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

7.   Energy :Energy is capacity to do work.

8.   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.

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

10.               Carbohydrates 
 
(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.

11.               Fats 
 
(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.

17.               Roughage

(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.

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

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

20.               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 mineralsDeficiency
Disease or DisorderMain SymptomsVitamin ANight blindnessPoor or loss of vision in darkness (night), sometimes complete loss of visionVitamin B1Beri-beriWeak muscles and very little energy to workVitamin CScurvyBleeding gums
 Vitamin DRicketsBones become soft and bent
 IodineGoiterGlands in the neck appear swollen, mental disability in childrenIronAnaemiaWeakness
  
21.               Beri-beri : It is a disease caused due to the deficiency of Vitamin B1. In the victim of beriberi muscles get weak.

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

Answer 2

Answer:our diet should contain sufficient quantities of different components because we require all the nutrients which are essential for the proper funtioning of our body.

Explanation: