Introduction to Terminologies of Food Science


Food means any substances eaten or drunk which meets the need for energy, body regulation and protection.  Food is that which nourish the body. Food may be processed, semi-processed or unprocessed but must be safe. According to Food Act of Nepal 2023; food means any unprocessed, semi processed or processed food or drinking substances which the human being generally consume and drinks include any spices, food additives, color or flavor to be used in any food or drinking substances.


Nutrition is the science of food, nutrients and other substances therein, about their action, interaction and balance in relationship to health and disease. Nutrition is the combination of process by which the living organism receive and utilize the material necessary for the maintenance of its components. Nutrition can be defined as the process by which an organism obtains food materials and uses them for growth, replacement, repair, respiration, reproduction and other activities performed by body. Nutrition is the result of food in the body. Animal have typical holozoic type of nutrition where organism obtain whole food and have developed special digestive tract modified for ingestion, absorption and egestion or defecation.


Nutrients are the chemical constituents of food that are needed by body in adequate amount in order to grow, reproduce and lead a normal, healthy life. Nutrients which our body cannot synthesize are called essential nutrients and thus must be provided in adequate amount through the diet. There are six essential nutrients. They are,

1. Carbohydrate

2. Protein

3. Fats and oils

4. Vitamins

5. minerals

6. Water

For, plants, no nutrients are essential because they can synthesize themselves.

Empty calories:

Those food that contains little or no essential vitamins or minerals. In other words, these food provide nothing of value to the body beyond calories. Few examples include;

  1. Treats like cakes, cookies, doughnuts
  2. Beverages like soda and energy drink
  3. Cheese, ice-cream and other full fat dairy
  4. Fast food like pizza, burger, French fries
  5. Junk food like chips, candy etc.


The world health organization (WHO) has defined health as “a state of complete physical, mental and social well-being and not merely absence of disease or infirmity.” The main determinants of health include;

1. Social and economic environment

2. Physical environment

3. Person’s individual characteristics and behaviors.

More specifically, key factors that have been found to influence whether people are healthy or unhealthy include

1. Income and social status

2. Social support networks

3. Education and literacy

4. Personal health practice and coping skills

5. Biology and genetics

6. Health care and services


Malnutrition is defined as pathological state resulting from a relative r absolute deficiency or excess of one or more essential nutrients. Common forms of malnutrition are;

1. Under nutrition

2. Over nutrition

3. Imbalance

4. Specific deficiency

Under nutrition:

It is defined as pathological state or condition which results when insufficient food is eaten over an extended period of time. Here, victim may suffer from protein energy malnutrition vitamin A deficiency (VAD), Iodine Deficiency Anemia (IDA), Iodine Deficiency Disorder (IDD) etc. or above all as a whole.

Over nutrition:

It is defined as pathological state or condition resulting from the consumption of excess quantity of food over an extended period of time. Important disease caused due to over nutrition are

1. Obesity

2. Hypercholesterolemia

3. Diabetes


It is a pathological state resulting from a disproportion among essential nutrients with or without absolute deficiency of any nutrients.

Specific deficiency:

This is a condition resulting from relative or absolute lack of individual nutrients. Example of such deficiency includes,

1. Protein energy malnutrition (PEM)

2. Iodine deficiency Anemia (IDA)

3. Vitamin A deficiency (VAD)

4. Iodine Deficiency Disorder (IDD)

WHO defines malnutrition as “the cellular imbalance between the supply of nutrients and energy and the body’s demand for them to ensure growth, maintenance and specific functions. Clinical forms of acute malnutrition are

1. Marasmus

2. Kwashiorkor

3. Marasmic Kwashiorkor


It is caused due to rapid deterioration of nutritional status in short time. It is the most common form of acute malnutrition in nutritional emergencies. It is characterized by severe wasting of fat and muscle which the body breaks down to make energy.


It is characterized by bilateral pitting edema in the body. Edema is the excessive accumulation of fluid in body tissues which results from nutritional deficiency.

Marasmic – Kwashiorkor:

It is the combination of both wasting and bilateral edema

Edible portion of food: It is also called edible portion (EP) and is defined as the portion of food that will be served to customer after food has been cut or cooked.

As purchased (AP) food: It is the portion of food that is in raw state before any cutting, processing or cooking has occurred.

Percentage yield: It is the factor used to determine how much food is lost as result of cooking, cutting and processing of food.

Balanced Diet: it is the portion of food which provides all essential nutrients in adequate amount and in adequate proportion. For normal people, daily energy requirement is 00 Kcal of which carbohydrate constitute 60%, fat 10% and protein 30 % of total diet.

Principle of balanced diet:

1. Use variety of food

2. Use natural/ unrefined food

3. Include whole beans and grains

4. Consume minimum amount of salt i.e. 5g/day

5. Fat content should be in adequate amount, especially Poly unsaturated Fatty Acids (PUFAS)

Guidelines for balanced diet preparation:

1. Select food from each of five food groups

2. Choose at least minimum number of serving from each food group. Example; eat bread at one time, rice at other time and patties for another time as a source of carbohydrate.

3. Choice within food group

  • Example 1: Rice may contain carbohydrate along with protein
  • Example 2: Milk and egg is a complete food
  • Example 3: If protein in needed, choose, milk, meat or pulses

4. Try to include at least one food from group (protein food group) in each meal.

5. Include seasonal fruits and vegetables

6. If carbohydrate, protein, fat are present in diet, other requirement are supposed to be fulfilled.


They constitute major portion of individual diet required for growth and energy. They contribute to the bulk energy needed for a living organism’s metabolic system, therefore they are required in larger quantities in our diet. They are;

1. Carbohydrate

2. Protein

3. Fat

4. Water


These are chemical substances that are required in small amount in our diet for proper body functioning and disease prevention. Classes of micronutrient includes

1. Phytochemicals and antioxidants

2. Vitamins

3. Minerals such as iron, cobalt, zinc, copper, iodine, selenium, molybdenum etc.

4. Organic acid such as acetic acid, citric acid, lactic acid, malic acid etc.

P.S: Minerals such as calcium, sodium chloride, magnesium, phosphorous and sulfur are sometimes called macronutrients because they are necessary in large quantities as compared to other vitamin and minerals. Although, micronutrients are needed only in small amounts, their deficiency leads to critical health problems.