We consume nutrients, which are compounds found in food. The body gets the energy it needs from nutrients to perform its daily tasks. They also aid in the body’s fast recovery from sickness and defence against illnesses and infections. We consume and digest it as well in order to get energy and aid in bodybuilding. Food is anything consumed to power the body, provide nutrients, build the body, repair worn-out cells, and maintain and improve a healthy body. It contains many of the foods and beverages humans consume, except alcohol, tobacco, and narcotics.


The study of nutrition focuses on food and how it affects people’s health. A nutritionist is a person who specialises in nutrition.

Types Of Food

1.  Solid or liquid: Examples of solid or liquid food are

  Solid foodsLiquid foods
  RiceCocoa drinks like Milo
  BreadBourn vita
  BeansFruit juice

2.      Local foods: Examples of local foods are Beans, Rice, Yam, Sweet potato etc      

3.      Imported foods: Examples of Imported foods are Milk, Stockfish, Butter, Pasta

4.       Cereals e.g Rice, Corn flakes, Wheat 

5.      Vegetables: okra, spinach, waterleaf, lettuce etc.

6.       Fruits e.g. mango, orange, lemon, apple, pear, guava, etc.

7. Foods eaten raw or cooked:  Foods eaten raw are lettuce, pawpaw, mango, banana, and cucumber. Foods eaten cooked are Yam, Rice, Beans, Meat, and Potato

Food can also be grouped into three categories according to the functions they perform in the body. These are

  1. Energy-giving food e.g. carbohydrates, fats and oils.
  2. Body-building food e.g. proteins.
  3. protective foods, e.g., vitamins and mineral salts.

Classes of food nutrients

Nutrition consists of carbohydrates, proteins, fats & oils, vitamins, minerals, and water.


These nutrients provide energy for the body. Foods high in carbohydrates are referred to be energy-giving foods. Carbohydrate-containing foods include yams, rice, cassava, bread, maize, pastries (made from flour), potatoes, pasta, and cereals, among others. Consuming natural foods (such as yam and cassava) as our daily carbohydrate intake is preferable to consuming processed meals (e.g. pastry and candy).


These are the nutrients required for tissue repair and development. Protein-rich diets are known as “muscle-building foods.” Protein-rich foods include beans, peas, eggs, peanuts, meat, and fish, among others. 

Fats and Oils

Fats and oils are also nutrient-rich meals that offer energy. In addition, they facilitate the absorption of fat-soluble vitamins. To avoid obesity, fatty meals must be taken in moderation, unlike carbohydrates. When a person has excessive body fat, they are labelled obese. Obesity may induce diabetes, hypertension, and high blood pressure.

Fats are found in both animals (including eggs, dairy products, and meat) and plants (nuts, olives, and avocados).


Vitamins are chemicals that protect the body from disease and infection. Additionally, they enhance the body’s use of proteins, fats, and carbohydrates

There are two sorts of vitamins: those that are fat-soluble and those that are water-soluble.

Since they are soluble in fat, vitamins A, D, E, and K are examples of fat-soluble vitamins.

Vitamins C, folic acid, vitamin B1 (thiamine), vitamin B2 (riboflavin), vitamin B3 (niacin), B6, and B12 are water-soluble vitamins.


Minerals are metallic substances used by the body. The health of bones and teeth depends on them. Use of major and trace elements to classify minerals. The body needs vast amounts of essential elements, including calcium, magnesium, potassium, sodium, phosphorus, chlorine, and sulphur.

Copper, fluoride, chromium, iodine, iron, zinc, and selenium are examples of trace elements the body needs in minute quantities.

Diets rich in vitamins and minerals are referred to be body-protecting foods. Minerals and vitamins may be found in milk, broccoli, dark-green leafy vegetables, oranges, pineapples, bananas, pawpaws, sweet potatoes, etc.


This is the most vital of all the nutrients in the diet. This is because, unlike other nutrients, humans cannot survive for more than 8 to 10 days without water. The percentage of water in the human body is 65%. Eight to ten glasses of water are recommended daily for adults. Water is necessary for both the absorption of water-soluble vitamins and the transfer of other nutrients. Water facilitates the evacuation of wastes, such as sweat and urine, from the body. Water is essential for proper digestion and absorption of other food components despite the fact that it contains no calories and is not a source of energy.

Classes Of Food and Composition

 Classes of FoodComposition
1.Carbohydrates e.g. Yam, Garri, Millet, PotatoCarbon, Hydrogen and Oxygen with Hydrogen and Oxygen in a ratio 2 of 1
2.Proteins e.g. milk, cheese, eggs, yoghurt, beans  Carbon, hydrogen, oxygen and nitrogen, sometimes sulphur and phosphorus
3.Fats and oils (lipids e.g. palm oil, groundnut oil, olive oil, animal fatsCarbon, hydrogen and oxygen fats are solid, while oils are liquid at room temperature.
4.Vitamins we have vitamins A, B, C, D, E AND K.Vitamins are made up of living organisms.
5.Mineral salts e.g. potassium, calcium, sulphur, phosphorus, nitrogenare chemical substances for human health
6.WaterWater is made up of oxygen

Deficiencies Diseases

Deficiencies may emerge when one or more of the basic food nutrients are absent from the diet. Below are a handful of these deficiencies and diseases caused by malnutrition


Insufficient consumption of protein is the cause of this disease. Symptoms of Kwashiorkor include stomach, ankle, and foot swelling, as well as tooth and hair loss.


This is caused by a severe lack of protein and carbohydrates. The affected child weighs less than 60 percent of what is typical for his or her age. A kid with marasmus will have loose skin on the thighs and upper arms, as well as a face in the form of a moon (the face of an elderly man). Additionally, his ribs and shoulder bones are visible.


This is caused by a deficiency of vitamin B (thiamine). Symptoms of beriberi include a rapid pulse, swollen lower legs, trouble breathing during exercise, vomiting, diarrhoea, and paralysis, among others. Under the supervision of a physician, vitamin B supplements may be used to treat beri beri. If not, the patient may be given vitamin B-rich foods, such as whole wheat.


This is caused by a deficiency of vitamin C. (ascorbic acid). A few of the symptoms of scurvy include rough skin, gums that bleed, tooth loss, and dry eyes and mouth. Citrus fruits (orange and lemon), tomatoes, papaya, guava, cabbage, and carrots are among the foods that may aid in the treatment and prevention of scurvy.


Chronic vitamin B (niacin) insufficiency is the cause of this disease. Pellagra symptoms include extreme skin redness, diarrhoea, hair loss, generalised weakness, and inflammation of the tongue.

Nicotinamide is used as a therapy. Both niacin and nicotinamide are vitamins.


Insufficiencies in calcium, phosphorus, and vitamin D are the underlying causes of this condition. Dental problems and bone fragility are symptoms. To treat rickets, increase your intake of calcium, phosphorus, and vitamin D. Light from the sun may be utilised to make vitamin D.

Balanced diet

A balanced diet has the appropriate quantities of each of the six nutritional groups. Rice and beans accompanied with a salad or green vegetables and a glass of water is an example of a balanced diet meal. A diet that satisfies the nutritional and quantity needs is deemed sufficient. An adequate diet is one that is balanced

The human body needs carbohydrates in greater quantity than proteins, lipids, vitamins, and minerals.

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