What is Nutrition?


Nutrition is consuming, absorbing, and using nutrients needed by the body to grow, develop, and maintain life. Nutrition Science deals with the role of food (dietary inputs) in health care.                                                                      

The essential requisites of Nutrition:

  1. Achievement of optimal growth and development, reflecting the full expression of one`s genetic potential.
  2. Maintenance of structural integrity and functional efficacy of the body tissues is necessary for an active and productive life.
  3. Sound mental health.
  4. Ability to withstand the inevitable process of aging with minimal disability and functional impairment.
  5. Ability to resist adverse effects of environmental toxins and pollutants and combat disease.

Nutrition Science is thus, the science of food, nutrients, and other substances therein; their action and interaction about health and disease. It also includes how individuals ingest, digest, absorb, transport, utilize nutrients and dispose of the end products.

It is concerned with all methods of growth, maintenance, and repair of living organisms that depend upon the digestion of food.

Any solid or liquid food which on swallowing can supply on or more of the following.

  1. Material from which body can produce movement, heat, or other forms of energy.
  2. Material for growth, repair, regeneration and reproduction.
  3. Substances necessary to regulate the processes of growth and repair.

Nutrition is a biochemical and physiological process in which an organism/individual uses food to support life. Nutrition is about eating a healthy and balanced diet.

We can become weak, sick, and even die without good nutrition. We need the proper nutrients for proper growth and to perform our day-to-day tasks.

7 Elements of Nutrition:

Carbohydrates, protein, fats, vitamins, minerals, fiber, and water are the important elements of nutrition for healthy growth and development.                                      

  1. Carbohydrates
  2. Minerals
  3. Vitamins
  4. Fiber
  5. Water
  6. Proteins                   
  7. Fats

1. Carbohydrates:

Carbs are the quick and first big source of energy in our body. Carbohydrate contains fiber, starches and sugars that are essential food nutrients that your body turns into glucose to give you energy to function. Too many carbs can be stored as fat, and can cause insulin resistance that leads to hunger.

There are 2 types of carbs;

  1. Simple carbs (sugar) these are quick source of energy, but can damage our metabolism and make us unhealthy.
  2. Complex carbs (starch) made up of long chain of glucose, that takes time to breakdown, which provide slower release of energy. They also contain fiber that aids digestion.

2. Proteins:

Every cell of the human body contain protein. You need protein in your diet to help your body repair cells and make new ones. Protein is also important for growth and development in children, teens and pregnant women. It makes up around 20% of our weight. It’s a building block that allows our bodies to do following processes;

  1. Build new cells
  2. Repair damaged cells
  3. Oxygenate us
  4. Aid digestion
  5. Regulate our hormones

3. Fiber:

Fiber is type of carbohydrate that is critical for helping us to digest our food. There are 2 types of fiber;

  1. Soluble Fiber__ this type of fiber dissolve in water and make a gel like substance that improve our digestion.
  2. Insoluble Fiber__ this type of fiber attracts water to your stool, which creates a healthier bowl, and may even reduce your risk of diabetes.

4. Fats:

Fats can also provide us energy, and helps us to absorb vitamins and build cell membranes, allow our muscles to move, and our blood to clot.

4 main types of fat:

  1. Saturated Fat: – these fats can have many health benefits like increases energy, improve bone health, and even reducing our cholesterol.
  2. Trans Fats: – these fats are terrible to our heart health. Found in fast foods.
  3. Monosaturated Fats: – these are one of the healthier fats, it contain anti-inflammatory properties and promotes growth and repair. Found in avocados, olive oils etc.
  4. Polyunsaturated Fats: – these fats are in moderation, but a balance must be stuck in between this and monosaturated.

5. Minerals:

Minerals are micronutrients that supports our many body functions such as metabolism, inflammatory responses and stay well-hydrated. Found in sea foods, green vegetables, citrus fruits, egg, milk, whole wheat foods etc.

6. Vitamins:

Vitamins are also micronutrients that support our many body functions and prevent from diseases. They promote eye health, skin and bone health and prevent us from many diseases like lower our risk of certain cancers.

7. Water:

Water is our basic and essential nutrient. It regulates our body temperature, improve digestion, reduce inflammation, remove toxins, protect our tissues and much more.

A healthy diet throughout life support growth, development and ageing, helps to maintain healthy body weight, promote healthy pregnancy outcomes and reduce chronic health diseases.                 

Good nutrition means your body gets all the nutrients, vitamins and mineral that are needed for best work.

8. Food Groups:

The nutritionists use different criteria for classification of foods depending upon the objectives of the exercise. The 2 criteria most commonly employed are based on functions and consumption patterns.

Food Groups Based on Functions:

Foods are required in the body to provide energy, promote growth, repair worn down body tissues and sustain the regulatory processes.

Nutrients, Their Function and Sources:

Energy GivingCarbohydrates



Bread, Rice, Sugar, Honey

Butter, Vegetable oils

Meat, Fish, Eggs, Pulses

Growth & RepairProtein

Mineral Elements

Meat, Legumes, Milk

Fruits, Vegetables, Salt

Protective/Control of body processesProteins

Mineral Elements Vitamins


Meat, Fish, Pulses

Milk, Fruits, Meat, Salt

Fruits, Vegetables, Meat

Beverages, Milk, Fruit juices

Food Groups Based on Consumption:

The Nutritionists divide foods into different groups. The most popular of such classes is a Food Guide Pyramid, introduced by the United States Department of Agriculture (USDA) in 1992.

The Food Guide Pyramid:

Changing dietary habits of people, life style and advances in food processing, have led the nutritionists, graphic designers and communications researchers to introduce the Food Guide Pyramid. At the apex are the recommendations for fats, oils and sweets that should be sparingly used.

Below this, meat, poultry, fish, dry beans, eggs and nuts on left side of group and on the right side is milk, yogurt and cheese group. The dietary recommendations are that only 2-3 servings for these should be taken in a day.

Next below these groups are 2 more groups, the fruit group (right) and the vegetable group (left). 2-4 servings of fruits and 3-5 servings of vegetables are consumed per day as per recommendations. The base of pyramid consists of bread, cereals, and pasta group. 6-7 servings are recommended from this group.                                                                                                                        


Food exists in in nature as simple assimilable materials or as complex mixtures of chemical compounds. The naturally occurring food compounds that are utilized by the human body and provide nourishment are called nutrients that perform functions such as energy giving, body building, etc.

Generally, nutrients are divided into 2 classes:

  1. Macronutrients
  2. Micronutrients

Macronutrients required in large quantities such as water, carbohydrates, fats and protein. These constitute bulk of the diet and supply energy for body activity and building blocks needed for growth and maintenance. They also regulate the body processes.

Micronutrients required in small quantities, milligrams to micrograms. These are vitamins and minerals that catalyze utilization of macronutrients.


The purpose of diet is to supply nutrients required for optimal growth. Diet comprises of foods (solid or liquid), or mixture of foods in the amount actually eaten, usually each day.       

Thus, if a person eats “chapati” with a glass of “lassi” in the morning and again in the evening, this would be his diet.

Balanced Diet:

Balanced diet is one that contain all nutrients in correct proportion required by an individual to promote and preserve good health. It should help to achieve and maintain desirable body composition and large capacity for physical and mental health.

Such diet generally leads to good nutritional status of a person. It is important that diet must contain foods from each group in appropriate proportions so that adequate nourishment is provided to the body.                                                                                                                        

For a normal adult man, a balanced diet consists of 2 or more portions from the group of protein and 3 or more from the group of fruits and vegetables each day.

Selection of protein should be from lean meat, fish, poultry, pulses and other legumes. Fat should be eaten in moderation. Cereals should be eaten to satisfy appetite and maintain a constant body weight.

For good health, adequate nutrient intake should be from dietary sources and not the pills, which can only deliver the selected nutrient.

Genetic Affect Nutrition:

Genetic affects your tolerance to certain foods. some people have lactose intolerance (dairy), gluten intolerance (wheat, barley, rye).

People who have this intolerance avoid those foods and have a number of risks. In nutrition, person, genetics or history must be seen when making diet plan.

Genetics may also affect your body’s processes like metabolism, absorption, and excretion.

Nutrition Affect Mental Health:

Brain and stomach share a close relationship. When we are eating balance and healthy diet like fruits and vegetables, they show positive affect on your mental and wellbeing. Stomach produces large number of neurotransmitters and is often result as “second brain”.

Eating healthy food produce good bacteria that stimulate more production of neurotransmitters in your body and improves your mood. On the other hand, eating unhealthy foods reduce or inhibit the production of neurotransmitters and worsen your mood.

Nutrition Effect on Immune System:

Eating healthy food make your immune system strong, which can make our microbiome healthy, reduce inflammation, improve you gut functions, and white blood cell’s function. It decreases the risk of diseases.

Mode Of Nutrition:

Modes of nutrition is a way by which living things get their food. There are 2 modes;

  1. Autotrophic (Autotrophs makes their own food such as plants that turn sunlight into food by photosynthesis.)
  2. Heterotrophic (Heterotrophs get their food from other sources by eating them such as humans.)
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