Proteins

Fourteen of these amino acids can be made within the body (non-essential) whilst eight (essential) must be obtained via food.

First Class Proteins (complete proteins) contain sufficient amounts of all the essential amino acids, having a High Biological Value (HBV) e.g. meat, fish, eggs and dairy products, non-animal sources include soy foods, tofu, soy milk and quorn.

Second Class Proteins (incomplete proteins) contain just some of the essential amino acids, Low Biological Value (LBV); vegetarian diets need to be carefully balanced, as vegetable proteins are second-class.
Vegetarians can obtain their protein requirements from such foods like beans, rice, tofu, quorn, nuts, fruits, vegetables and seed foods. These foods contain the eight essential amino acids, however not all in their sufficient level for the liver to synthesis correctly. Combining incomplete proteins together will improve your protein intake, e.g. Rice with Beans - Wheat with Beans - Nuts with Vegetables - Grains and Pulses.

Protein drinks and shakes are often high in whey protein and are a good source of protein supplement, however are bodies are designed to actually digest food, so aim to actually eat solid foods rather than rely on a liquid diet.

Functions of Protein
Proteins are used to build the structures that make up our bodies, growth and repair.

Muscle tissue - About three-quarters of the dry weight of human muscle tissue, is made up of protein. Structural tissues such as tendons, skin, hair and nails are all made from protein.

Bones - Once the minerals such as calcium have been removed, you are left with a protein called collagen.

Organs - Your body's vital organs such as liver, kidneys heart and lungs are all made from proteins.

Functional proteins are specific to enabling the body to function physiologically.

Enzymes - Millions of chemical reactions occur in our body cells each day, these enzymes (peptides) help speed up the reactions.

Hormones - Released into the blood stream to act as signals for the body, and aid in regulating proper body function.

Immune system - Specialized cells that aid to maintain good health.

A source of Energy

Protein amino acids can be converted to glucose, in order to fuel the muscles, however it is important maintain glycogen energy levels within your muscles to help prevent excessive protein breakdown.

During exercise, or strenuous work, the body will go into a self-catabolism state, actually breaking down the structures within the body. This is because micro tears are caused when our bodies are placed under physical stress, and the body then breaks down the structures worked, in order to rebuild them stronger.

This building-up process is called Anabolism, it occurs after exercise, during rest periods, providing the essential amino acids (proteins) have been supplied to the body.

This why correct protein intake and rest is essential for optimum body performance for both athletes and healthy living.

Recommended Amounts:

A good general rule of thumb for determining protein requirements would be one gram of protein for every kilogram (2.2 lbs.) of body weight.

This rule does not take into account a person's body composition, activity level, age or for women only, pregnancy.
Aim to have the amount balanced out through out your meals, as your body cannot store protein.

The following gives an outline for protein consumption.

Protein deficiency may lead to abnormalities of growth and tissue development. The hair, nails and skin especially will be affected and muscle tone will be poor.

Loss of body protein can occur as a result of particular bodily stresses such as surgery, hemorrhage, wounds or prolonged illness.

At times of stress, or exercise it is necessary to consume extra protein in order to rebuild or replace used or worn out tissues.

Our bodies can't store excess protein; likewise our bodies can only absorb around 25 - 30 grams of protein per meal. The excess protein needs to be broken down (deamination) which takes place in the liver and involves splitting the amino acids into an amino group and acid group.

The amino group contains nitrogen, that can't be stored and becomes converted to ammonia, which is toxic to the body, and as such is converted to urea, and sent to your kidneys to pass through your bodies urinary system. Kidney damage can be caused due to an over-load, if excess protein is eaten, especially in large amounts such as in the Atkins Diet.

The acid group contains carbon, hydrogen and oxygen, which are then converted to carbohydrate (CHO). As with all excess CHO, if not used, it will be converted to adipose tissue (body fat).

When looking at planning your meals look at consuming good quality proteins, these may be slightly more expensive, as you should look for lean cuts of meat - chicken / turkey breasts - all types of fish, especially salmon and egg whites.

If you cant afford the good quality proteins, non fat or less than 2% cheese - cottage cheese - sour cream and sugar free yogurts are good non meat sources, or look at cheaper very low fat sliced or minced meats, especially chicken or turkey.

Proteins to avoid are those that are high in fat, these may be full fat dairy products, heavy fat meats such as bacon.

Nuts and seeds are healthy, however they generally high in both healthier fats and proteins, the main problem is that they are very easily consumed - avoid over eating, especially nuts.