Nutrition: Nutrition can be defined as the science of food and its relation to health. It can also be referred to as nourishment. These sustain life.

Pirre and Brown (1984) define nutrition as the science that interprets the relationship of food to its functioning in the living organism.

People tend to live or live to eat. Those who eat to live are less than those who live to eat, but when you live to eat you are rather wanting to die because you will be prone to health challenges.

Nutrition may also be defined as the utilization of food by living organisms.

Food is any substance, either solid, liquid, or fluid, that can enhance the continuity of life. It has been scientifically proven that man needs both food and water to live. Therefore, a man may only survive 7 days without H₂O and 14 days without food.

All food substances contain nutrients. These food nutrients are chemical constituents in food that are essential for life and must be supplied to the body in suitable amounts.

Some are needed in large quantity and are called macronutrients, while some are needed in infinitesimal/small quantity and are called micronutrients.

Examples:

Macronutrients: Carbohydrates, proteins, fats and oils.

Micronutrients: Minerals, vitamins, fiber, etc.

To a biochemist, nutrition can be classified into three categories:

1. Undernutrition

2. Overnutrition

3. Ideal nutrition

Ideal nutrition is the concern of everyone and it involves all the food nutrients consumed in correct or right proportion.

It is also known as a balanced ration or balanced diet.

However, overnutrition is the challenge of developed countries while undernutrition is a challenge of developing countries.