The 6 Classes Of Food With Examples, Sources & Their Functions

Knowing the different classes of food is very important, because it helps us to track our dietary intake. Once you know the classes of food, it will give you ample opportunity to know the kind of food that you should consume to keep your body fit.

Food is very important for the proper growth and functioning of the body system. Without good food, the functioning of the body system may witness disruption due to a deficiency of food nutrients. Hence, eating a balanced diet is highly recommended but that could only be possible if you know the Classes Of Food and how it works.

Primarily there are Six Classes Of Food but for intensive studies, the classes may be more than six. However, in this article, we are going to be looking at only the six classes of food and what each does in our body system. Keep scrolling.

Each class of food has a particular function that it performs in the body, hence when you are dining, it is best to ensure that the food you are consuming contains all the classes of food in the right proportion to avoid nutritionally related diseases like kwashiorkor and marasmus.

What Is Food?


In the simplest term; Food is any substance or material that we eat(liquid or solid) to nourish or replenish our body, keep us healthy, and enable us to grow with a lot of energy that would help us to carry out physical activities.

From the definition of food, we can see that food can come in either solid or liquid form. But the most important thing is that it is needed for the proper growth and functioning of the body system.

Importance Of Food


The importance of food cannot be overemphasized because without food we may not be able to carry out of daily activities. Apart from that, we need food to grow and function properly. Without much ado, the importance of food is summarized below:

  • Food helps us to grow properly
  • It is needed for the repair of worn-out cells and tissues
  • Food provides energy that we use to do work
  • It protects the body from diseases
  • It aids in regulating the body temperature
  • We can also sell our food to get money
  • Food helps to eradicate hunger.

Classification Of Food


As we all know that there are six classes of food, but how well do you know their chemical constituents, their functions, and what their deficiency may cause? If you don’t know much about it, then you need to flow with me in this section as I am going to be doing justice to them shortly. 

The 6 Classes Of Food With Examples, Sources & Their Functions
Classes of food with picture

The six classes of food are classified below

  • Protein
  • Mineral
  • Carbohydrates
  • Water 
  • Vitamin 
  • Fat and oil 

But for easy comprehension, we are going to be taking a look at each of them one after the other. Keep scrolling through the article.

  •  Protein

Protein is an essential organic foodstuff that can be found in both plant and animal foods. The end product of protein digestion is Amino Acids. It is primarily known as body-building food.

Sources Of Protein

The primary sources of protein include snails, insects, melon, peas, grains, beans, oil beans, soya beans, breadfruit, egg, meat, fish, milk, cheese, shrimp, etc.

Function Of Protein

There are numerous functions of proteins some of which are summarized below

  • It is needed for building new tissues 
  • Children need it for proper growth and development
  • It is needed for hormones and enzymes formation in the body
  • It can be generated during gluconeogenesis.

Protein Deficiency

If somebody lacks protein, that person is liable to suffer from any of these diseases. The diseases caused by protein deficiency include

  • Anemia
  • Kwashiorkor
  • Finally, the person won’t grow properly.


  • Vitamins

This is the class of food that is necessary for good health and maintaining the body.

Generally, there are two main types of vitamins, Viz; Fat-soluble vitamins (vitamins A, D, E, and K) and water-soluble vitamins(vitamins B and C).

Having said that, we are going to be taking a look at classes of vitamins. The table below summarizes it.

S/N Class Of Vitamin Function Sources Deficiency
1. Vitamin A (Retinol) •It is needed for good vision              •Good skin and hair

•Promote growth        •Formation of teeth and bones 

margarine, egg palm oil, cheese

carrots, liver, fish, vegetables, butter, etc

•Unhealthy skin and hair

•Digestive problem

•Poor vision and night blindness

2. Vitamin B (B complex) •It Promotes healthy skin and hair

•It is needed for the general maintenance of health

Milk, vegetables, Fish, egg, rice, soya bean, liver. •Beri Beri       •Poor appetite and loss of memory


3. Vitamin C (Ascorbic acid) •It is needed for forming substances that bind cells together e.g in blood capillaries, teeth, and bones

•It increases resistance to infection

Strawberries, vegetables,

fresh citrus, oranges, lemon, 

Lack of Vitamin C in the body causes 

•Scurvy          •Bleeding gum and        weak teeth

•Delay healing

4. Vitamin D (Cholecalciferol) It is important for normal bone and teeth development Egg, butter, milk, liver, fish oil, sunlight, etc It causes rickets in children

Weak bone and teeth

5. Vitamin E (tocopherol) •It enhances heart and muscle functions

•It also enhances reproduction

Vegetables, eggs, oranges, fresh fruits, etc.
6. Vitamin K (Phylloquinone) •It enhances digestion     

 •It aid in blood clotting

vegetable, cereal, meat •It causes Constipation      •It leads to bleeding

Mineral Salt

The mineral salt is very vital in the body because it is needed for the regulation of metabolic processes and normal body development.

The major minerals needed by the body include calcium, iron, sodium, iodine, phosphorus, and fluorine.  


They are gotten from green, vegetables, eggs, beans, liver seafood, etc


  • It is needed for healthy growth.
  • It needed for the formation of strong teeth and bone
  • It is also needed for hemoglobin formation
  • It is required for blood clotting


Lack of mineral causes

  • Goiter, muscle cramp, tiredness
  • It leads to poor functioning of the body.


It is made up of three major elements which are carbon, hydrogen, and oxygen. It is primarily known as energy-giving food. The end product of carbohydrates is glucose.


The primary source of carbohydrates is ripe plantain, rice, honey, bread, yam, maize, sugar, cassava, potatoes, oat, millet, etc.

Functions Of Carbohydrate


Carbohydrates are known as energy-giving food. But apart from that, it has other functions which are enumerated below

  • It helps in the production of body heat
  • It produces energy for muscle contraction.


A lack of carbohydrates in the body can cause

  • It may reduce the function of the nervous system
  • It causes marasmus in children


It is the major constituent of the body. It contains oxygen and hydrogen as the major elements.


Direct intake, fruits, vegetables, etc.


  • It is needed for homeostasis, absorption, reproduction, transportation of other food nutrients, etc.


Lack of water in the body causes  dehydration and malfunctioning of the 

organs and system

Fats And Oil

The major fats in our diet usually come from animals while the oil is major in plant origin. At room temperature, the oil is usually liquid while the fat is usually solid. The end product of fats and oil digestion is fatty acid and glycerol.


vegetable oil, nuts, cheese, palm oil, groundnut oil, cream, butter, cod-liver oil, and meat margarine.


  • It supplies heat and energy to the body
  • The help in nourishing the skin
  • They protect organs from shock and injury
  • It stores and transfers Vitamin A, D, E, and K, etc.


The lack of fats and oil in the body causes the following

  • Poor functioning of body organs
  • It leads to dryness of the skin
  • It leads to a lack of energy


What Are The 6 Classes Of Food?


The six classes of food are protein, vitamins, carbohydrates, minerals, water, and fat.

What Are The 7 Food Classes?


The seven classes of food are proteins, fats, water, dietary fiber, minerals, and carbohydrates.

What Are The 3 Main Classes Of Food?


The three major classes of food are fats, proteins, and carbohydrates. They are also called macromolecules and we consume them daily.



There are six classes of food and our body needs them for proper growth and development. 

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