Nutrition: strictly speaking

Nutrition is the biological process through which organisms assimilate food and liquids to enable them to function,grow and keep said process working normally.Nutrition is also the study of the relationship between food and health,especially in order to identify an optimal diet.

 

Diet and nutrition are not synonyms,but separate terms:

• Nutrition refers to the nutrients found in foods.It encompasses a collection of involuntary phenomena that occur following the ingestion of food:digestion; absorption,or the passing of food nutrients or components into the blood from the alimentary canal; metabolism,or the chemical transformation of said nutrients or components within the cells; and their excretion,or elimination,from the organism. 
• Diet refers to a collection of voluntary and conscious acts that involve the selection,preparation and ingestion of foods – phenomena that are closely related to a person’s sociocultural and economic situation (their environment) – and determine,to a large extent,their dietary habits and lifestyle.

An adequate diet is one that meets:

• Energy requirements,through the adequate ingestion of energy nutrients,such as carbohydrates and fats.A person’s energy requirements depend on their level of physical activity and energy expenditure.
• Plastic or structural requirements,through the ingestion of proteins.
• Requirements for non-energy micronutrients,such as vitamins and minerals.
• Hydration needs,through the consumption of water. 
• Dietary fibre requirements.

Correct dietary guidelines are shown as food pyramids,like the NAOS Pyramid.

Nutrition is a consequence of diet; each person’s supply of nutrients and their nutritional condition depends on the foods that make up their diet and in what proportions they are consumed.