Food and Nutrition

Food

Food is anything that can be taken by mouth, digested in body and gives useful nutrition. In other words, food is any substance consumed to provide nutritional support for the  body. It is usually of plant or animal origin, and contains essential nutrients, such as fats, proteins, vitamins, or minerals. The substance is ingested by an organism and assimilated by the organism's cells to provide energy, maintain life, or stimulate growth. Combination of food constituent in a proper combination makes a balanced diet. Balanced diet is the  balanced intake of nutrients  required for proper continuation of life processes. A balanced diet contains various groups of nutrients, particularly carbohydrates , proteins, and vitamins. It meets a person's caloric need. The components of a balanced diet differs according to age, sex, physical activity and the physiological state. Children need more proteins for growth and development. A person who works very hard needs more intake of carbohydrates and fats.

Nutrition

Nutrition is the process of proper intake of food, which is needed for continuing life processes. Oxford Advanced Learner's Dictionary has defined nutrition as " the process by which living things receive the food necessary for them to grow and be healthy " . Proper nutrition maintains the proper functioning of body tissues and cells. It is essential for survival. It is said that individual's health is a result of what he eats. Therefore, an individual must maintain all sorts of food from different groups so that body can fulfill its requirements for proper functioning and development. The food that we eat should contain appropriate nutritive values. 

Objectives of Foods 

General objectives of food are as follows; 

1. To construct healthy body 
2. To gain energy 
3. To regulate the physiological processes of body 
4. To protect body from diseases and infirmities 
5. To develop psychological state of person 
6. To assist in socio-cultural functions 
7. To develop personality 

Classification of foods 

Food is categorized on the basis of sources or presence of nutrients contained in them. On the basis of sources of foods, they can be categorized into the foods from animal sources and food from plant sources. 

a) Food from animal sources: The category includes the foods like milk, meat, egg, etc. 

b) Foods from plant sources: This category of food includes grains, cereals, fruits, vegetables, lentils, oils, etc. 

On the basis of function of foods, they are categorized into the followings: 

a) Heat and energy yielding foods 

It is the food containing carbohydrates and fats, which are responsible for production of heat and energy in our body. They are needed more in comparison to other category of foods for our body. There must be 50-60% of carbohydrates and 30-35% of fat in the balanced diet. They can be obtained from the foods including rice, maize, potato, sweet potato, honey, sugar, wheat, yam, oil, butter, ghee etc. 

b) Body building food 

The foods containing different forms of proteins are known as body building foods as they are essential for production of new cells and tissues. There must be 10-15% of proteins in daily foods for our body. They are necessary for the growth and development. Animal proteins can be obtained from fish, meat, egg, milk, etc. Plant proteins can be obtained from gram, beam, lentil, etc. 

c) Protective food

It is a set of foods containing minerals and vitamins, which are responsible for developing protective power of the body against germs and diseases. They can be obtained from food items including vegetables and fruits. 

General outline of nutritional requirements 

Our body is composed of several kinds of tissues and organs. They need peculiar set of nutrition to function properly. Therefore, we need a variety of nutritional components to remain healthy. On the basis of presence of nutritional components, our body is composed of the following proportion of nutrition: 

Constitution of our body on the basis of nutrients
Water	61.6%		Mineral	1.5%
Protein	17.0%		Carbohydrate	6.1%
Lipid/Fat	13.8%		Total	100%

Water is the major constituent of our body. It occupies approximately more than sixty percent of the total body mass. Carbohydrates are consumed at maximum amount with our food) But most of them are used to produce energy and a significant amount is lost with excretion. Only about 6.1% of carbohydrate remains stored in our body. There is 17% protein stored primarily in muscle tissues. Minerals are stored in bones, blood and muscles. There is negligible amount of vitamins present in our body. Therefore, we should include them regularly in our food. 

a) Carbohydrates

Carbohydrates are the complex organic compounds consisting of carbon, hydrogen and oxygen as constituents. They get combined with oxygen in the body and produce required energy needed for it. They are main source of heat and energy in the body. They can be obtained from the foods including rice, maize, potato, sweet potato, sugar, honey, cane, wheat, barley, sweet fruits, etc. Carbohydrates occupy more than half of the total food in a balanced diet., One gram of carbohydrate produces 4.1 calories of energy in human body.

b) Fats 

Fats can yield more energy than carbohydrates. It is stored in subcutaneous layer and around the intestine. They also prevent the loss of heat from the body. Fats are needed 30-35% of total nutrients in a balanced diet. Fats can be obtained from butter, ghee, meat, fish, egg, milk, oil, etc. Fats can produce more energy than that of carbohydrates. One gram of fat produces 9 calories of energy in human body. Fat is not preferred for production of total energy required as it has various adverse effects including obesity in human body.

c) Proteins

Proteins help in reconstruction and repair of lost and worn-out tissues of body cells at any part. Proteins are mainly of two types: animal proteins and plant proteins. Proteins are complex molecules synthesized by assembling aminoacids, carbon, sulphur, oxygen, hydrogen, nitrogen, phosphorus, etc. Proteins are required for building up tissues in the body as well as repairing the worn out tissues of the body. Proteins are obtained from animal food product like meat, egg, milk, etc. and plant products like beans, lentils, gram, pea, etc. Proteins can also produce small amount of energy. They produce energy if there is severe scarcity of carbohydrate and fat in body.

d) Minerals

Minerals are needed for protection of our body from different diseases. They are also required for the normal functioning of the body. They are naturally found in the soil and in the  body of living things. Iron, calcium, zinc, copper, phosphorus, iodine, sodium, magnesium, molybdenum, potassium are some examples of minerals. Though, minerals are needed in small amount, they are crucial for body metabolism. They are taken from the soil by plants. When we take foods of plant prodcuts, we obtain minerals. Minerals are also stored in animal products. Minerals are found in meat, milk, egg, fish, wide range of vegetables and fruits. 

e ) Vitamins 

Vitamins are also grouped in nutrient required for protection. These do not supply energy but have protective functions. Vitamins can be classified as fat soluble (vitamins A, D, E and K ) and water soluble ( Vitamins B complex and C). The sources of vitamins are egg, fish, meat, milk, vegetables, fruits, and external coating of various grains.

f) Water

Water is the main constituent of human body. Water occupies about 60 to 70 percent of the total body weight. We need to have safe drinking water everyday. Water maintains the body temperature , transportation of various substances within the body, balance of electrolytes and salts , absorption of digested food from alimentary canal, as well as excretion of wastes from the body. Body fluids like lymph, blood, hormones, and all secretions contain water as its basic component. It also forms excreta and the waste products from the body.

Characteristics of Quality Food

The food items which have necessary nutritive values and free from adulteration are called quality food. The quality foods composition and contents are printed on the packaging. It should be examined by the concerned authority. There is a legal provision of providing Nepal Standard (NS ) Mark for the quality products brought in the market. If quality food is not supplied, it  affects our health adversely. Food is regarded as the fuel of life. It is very essential for survival. Common characteristics of quality food is mentioned below:

1. Quality food provides necessary heat and energy required for the  body.
2. Quality food maintains homeostatic features like temperature, blood pressure, limit of hormones, salts, etc. in the body.
3. It promotes growth by replenishing and repairing tissues. 
4. It helps to regulate body processes and functions properly.
5. Quality food protects body from disease.

Quality food needs the inclusion of following five foods:

1. Milk or any of the dairy product.
2. In order to supply  protein, there need any one item from meat, fish or egg for non-vegetarian people and lentil, bean, gram, pea, or any one source of plant- protein for vegetarian people.
3. Any one item of carbohydrate rich foods like rice , wheat, barley etc.
4. Any one item of green vegetables.
5. Any one item of fruits like mango, orange, banana, guava etc.