Immunology is a crucial area of study within Biology Topics, exploring the immune system.
Balanced Diet – Meaning and Food Groups
The food which we eat during the whole day is called our diet. A diet consists of many food items made from cereals (like wheat and rice), pulses, fruits, vegetables, meat, fish, eggs and milk, etc., which supply all the nutrients to the body. The diet which contains adequate amounts of all the nutrients such as carbohydrates, fats, proteins, vitamins and minerals (sufficient for the normal growth and development of the body), is called a balanced diet. A balanced diet also contains sufficient amount of water and roughage.
Some food items are rich in carbohydrates, some are rich in fats, while others may contain more of proteins, vitamins and minerals. No single food item can provide us all the essential nutrients in adequate amounts. So, in order to make a balanced diet, we should include a number of different food items in our daily meals which, taken together, provide us all the nutrients in adequate amounts. We should also drink sufficient water and eat roughage-containing foods.
A balanced diet should contain enough food items from each of the following groups:
- Cereals (wheat and rice preparations), Potatoes, Sugar, etc. (to provide carbohydrates).
- Butter, Ghee and Oil (to provide fats).
- Pulses (Dal), Peas, Milk, Cheese, Fish, Meat, Chicken and Eggs, etc. (to provide proteins).
- Vegetables and Fruits (to provide vitamins, minerals and roughage).
A balanced diet is not the same for all age groups or occupations. A balanced diet depends on the age of the person and also on the occupation of the person (type of work done by the person). This is discussed below.
Dependence of Diet on Age
A child and a grown up man are of different age, so the balanced diet of a child is different from that of a grown up man. A growing child needs more proteins in his diet than a grown up man (in comparison to his body weight). This extra protein is needed to make the body tissues of the fast growing child. So, the diet of a growing child should contain more of protein-rich foods than the diet of a grown up man. A growing child also needs more minerals like calcium and phosphorus for the formation of bones, than a grown up man.
Dependence of Diet on Occupation
The job or profession of a person is known as his occupation. Different jobs involve different amount of work. The balanced diet depends on the amount of work we do in our occupation. So, the balanced diet of a man doing hard physical work is different from another man doing normal work. For example, a man doing hard physical work (like a labourer or carpenter) needs more carbohydrates in his diet than another man doing normal work. This is because he needs more energy for doing hard physical work, and this extra energy is supplied by including more of carbohydrate-rich foods in his diet.
Many people like to eat a lot of fat-rich foods such as fried foods (;samosa, tikki, poori, pakoda, etc.). This is not a good habit. Eating too much of fat-rich foods is harmful for our health. It can lead to a disease called obesity (motapa). All of us should eat a balanced diet to remain healthy.
Avoid Wasteful Pre-Cooking and Cooking Practices
Most of the raw food materials are not fit for eating as such. The raw food materials are washed, peeled, cut and cooked to make them fit for eating. Some nutrients present in food materials are, however, lost during the pre-cooking and cooking practices, which should be avoided. This will become more clear from the following discussion.
The various wasteful pre-cooking practices which lead to the loss of nutrients are :
- Repeated washing of rice and pulses,
- Washing of fruits and vegetables after they have been peeled and cut, and
- Taking off thick peels from fruits and vegetables.
Washing of food materials before eating raw or cooking is useful because it removes dust, harmful germs and chemicals, etc., sticking to their surface. But repeated washing of food materials is harmful because it leads to the loss of nutrients. For example, repeated washing of rice and pulses (dal) removes the water soluble vitamins and some minerals from them and hence lowers their nutritive value.
The washing of fruits and vegetables after they have been peeled and cut, removes the water soluble vitamins and some minerals from them. This lowers their nutritive value. To avoid the loss of vitamins and minerals, the fruits and vegetables should be first washed, and then peeled and cut.
The skin of most fruits and vegetables contains vitamins and minerals. In some homes, thick peels are taken off from the fruits and vegetables, which leads to the loss of vitamins and minerals. If the peeling of fruits and vegetables has to be done, the peels removed should be as thin as possible to prevent the major loss of vitamins and minerals.
Cooking of food has many beneficial effects. Cooking improves the taste of food and also makes it easier to digest. At the same time, cooking of food may also lead to the loss of nutrients.
The various wasteful cooking practices which lead to the loss of nutrients are :
- Cooking the food at high temperature, and
- Throwing away water in which food is first boiled.
Vitamin C gets destroyed easily by heat during cooking. So, when food is cooked at a high temperature (as is done in the process of boiling, steaming, roasting, baking or frying), then the excessive heat destroys a major portion of vitamin C. We should, therefore, include some fresh fruits and raw vegetables (as salad, etc.) in our food to get the required vitamin C.
If the excess water in which a food material is boiled during cooking, is thrown away later on, then some of the proteins and considerable amount of minerals present in the food are lost. This should be avoided.