Nutrients are the chemical substances found in foods necessary for health; they can be broken down into six groups: Carbohydrates, Water, Fat, Vitamins, Proteins, and Minerals The body uses carbohydrates, proteins and fat to produce energy.

Carbohydrates

Carbohydrates are classified as simple (sugars) and complex (starches) and are found in most foods except for pure fats. During exercise the body predominantly uses carbohydrates for fuel. To optimize energy carbs should be the major nutrient in one's diet 50-65%; foods rich in complex carbohydrates should be consumed every meal.

Proteins

Proteins are necessary for body growth, repair, making and maintaining enzymes, antibodies and blood. Proteins are comprised of amino acids. The human body uses 22 amino acids, 9 of these cannot be made by the body and are called essential amino acids, the body manufactures the other 13 nonessential amino acids. Foods containing all of the 9 essential amino acids are called complete proteins.

Complete proteins usually come from animal based foods such as meat, fish, eggs and dairy. Incomplete proteins are those missing some of the essential amino acids, in order to form complete protein these need to be eaten in combination with other foods in a 24 hour period. Incomplete protein foods include vegetables, grains, legumes and nuts.

Fat

Fats are the most energy dense of all three energy-containing nutrients. Fat is used to produce hormones, immune system components, and cell membranes. Fats also contain fat-soluble vitamins. There are three primary categories of fat; saturated, monounsaturated and polyunsaturated.

Saturated fat comes from animal fats such as beef, pork and dairy as well as from some tropical sources like coconut and palm oils.

Monounsaturated fat comes from olives, peanuts, avocados and canola.

Polyunsaturated fat comes from most plant oils such as sunflower, corn, sesame, soy and flaxseed. Cholesterol is found only in animal fats and should be avoided as much as possible.

Fitness Tips

How to apply knowledge of the body to increase fitness gains
There are certain principles of training that are crucial to understand in order to get the best gains in fitness.

· Adaptation - the body adapts to physical stresses imposed on it.

For example if the body experiences regular aerobic exercise the cardio respiratory system will respond by becoming more efficient, increased fitness. Another example would be if someone performs the same stretch regularly, over time flexibility will improve as the body adapts. What adaptations occur is dependent on the type of training done.

· Progressive Overload - As the body adapts to imposed physical stresses it will eventually reach a plateau where no more gains are met. In order to achieve further improvements the load - the intensity - must be progressively increased.

· Recuperation - During periods of exercise the body experiences a breakdown effect, the catabolic effect. During rest periods the body experiences a building effect, the anabolic effect. In order to get the best results there must be sufficient rest periods for building to occur, the more intense the workout the greater the rest required.