Food is any material consumed to supply nutrition to an organism. Generally speaking food is generally of animal, plant or fungus origin, and consists of necessary nutrients, including vitamins, proteins, carbohydrates, and minerals. The nutritional value of food is intended to increase the life and health of the people who eat it, and may be in accordance with the person’s stage of life, physical activity, preferences, etc. The nutritional content of food is measured by its caloric value, nutrient content per serving, quality (number and type) of the ingredients used, and safety. Nutrient content per serving is calculated by taking the weight of a serving of food and multiplying it by the number of calories in a serving of food.

In food, nutrients that are needed by the body in large amounts are present in abundance, including vitamins A, B-complex, C, E, and K, fat, protein, carbohydrate, minerals, and amino acids. These nutrients enhance health and prevent illness. The human body requires about two thousand calories per day to maintain normal metabolism; however, even when one gets the right amount of food and exercises, there is still an insufficient supply of energy for the body, resulting in lack of proper nutrition. Thus in order to counter this problem, various nutrients have been added to food, for example vitamins and minerals to improve the immune system, control cholesterol levels, prevent diseases, heal cells, etc.

There are three major categories of nutrients: carbohydrates, protein and fats. Carbohydrates provide most of the calories we need. They include fruits, vegetables, breads, cereals, potatoes, rice, etc. Protein on the other hand consists of milk, meat, eggs, fish, nuts, legumes, vegetables, fruits, and grains. Fats provide us with energy, which is either lost or utilized. A diet rich in nutrients and with the right proportions of macronutrients (the nutritive value of a food) will result in optimal health.