The human diet must provide enough calories to meet daily energy needs, together with essential amino acids, essential fats, minerals and vitamins for proper metabolism. The daily average required of these nuntrients are found in the Recommended Dietary Intake (RDI) tables.
Calories are the measurement of energy stored in foods. The human body uses food as its fuel. In the absence of food, the body uses its reserve fuel (glycogen).
Essential amino acids
Amino acids are the building blocks of protein. When plant or aminal protein is consumed, it is broken down into its amino acids. These can then be used in human metabolism. An absence of one or more essential amino acids over a period of weeks to months can lead to malnourishment symptoms of apathy, diarrhea, inactivity, failure to grow, flaky skin, fatty liver, and edema of the belly and legs.
Three key fatty acids are needed in the diet: linoleic acid, linolenic acid, and arachidonic acid. These are found in grain, vegetable or nut oils.
Only small levels of minerals are needed for proper nutrition. These minerals are scavenged from many sources and it is rare for anyone consuming a regular diet to have a deficiency.
Vitamins serve as metabolic assistants in many vital bodily functions. Vitamins A, B(1,2,3,12), C, D, E, K, and folic acid are required. Defeciencies lead to specific diseases such as beriberi and ricketes.
Effect of storing foods on nutritional content.
For the most part, the body can still use calories, amino acids, fats, and minerals that have been chemically changed during storage. Vitamins are the only nutrient group that can break down to an unusable state.