Simply because of what they do in the body. Without spending all night (I'm going to bed in a minute) here is a quick copy paste that I just grabbed to save time--bottom line, they both do so much from a muscular and metabolic standpoint counting them as whole proteins is fine, AS LONG AS THEY ARE USED IN CONJUNCTION (not neccesarily taken at the same time) with whole protiens.
If you prefer not to count them that way, fine. But based on experience they are much more anabolic than plain "complete" proteins when used in conjuction with an already high protein diet.
BCAA’s are Branched Chain Amino Acids consisting 3 essential amino acids leucine, isoleucine, and valine. They are considered essential amino acids because human beings cannot survive unless these amino acids are present in the diet.
They are called BCAA's because they structurally branch off another chain of atoms instead of forming a line. Together they comprise approx. 1/3 of human muscle tissue. The BCAA's consist of 3 essential amino acids: leucine, isoleucine, and valine.
Studies have shown that BCAA's help to stimulate protein synthesis and inhibit its breakdown, so BCAA's have powerful anabolic and anti-catabolic effects on the body.
BCAA's have a very important role in sports nutrition. If the liver's glycogen stores are depleted during exercise, the body manufactures glucose from other substrates, including proteins & amino acids. The exercising muscle releases BCAA's to be broken down to make the amino acid alanine, which is then transported to the liver for conversion to glucose. BCAA's are unique in that they can also be converted and shuttled directly into energy production in muscle itself. It is essential that the athletes’ diet is supplemented with a protein source rich in BCAA's (i.e. whey protein) to reduce muscle breakdown, maintaining exercise performance and intensity and assist muscle recovery and growth. Therefore, unlike other amino acids, BCAA's provide energy directly to the muscle tissue. In fact during prolonged athletic activity, BCAA's serve as a valuable fuel source - providing as much as 15% of the body's total energy needs. If you do not consume enough BCAA's when needed (i.e. during intense physical activity, illness, or dieting) you may breakdown muscle to liberate BCAA's for more urgent demands in other tissues.
In conclusion BCAA’s have been shown to assist with;
• energy production
• decrease exercise-induced protein degradation and/or muscle enzyme release (which is an indicator of muscle damage)
• muscle growth,
• BCAA supplementation during intense training may help minimize protein degradation and thereby lead to greater gains in FFM (fat free mass).
• and recovery fat burning
Glutamine is highly in demand throughout the body. It is used in the gut and immune system extensively to maintain optimal performance. 60% of free-form amino acids floating in skeletal muscles is L-glutamine. L-glutamine plays a very important role in protein metabolism, and it appears to be a very important nutrient for body builders. When supplemented, it may help body builders reduce the amount of muscle deterioration that occurs because other tissues that need glutamine will not rob the glutamine stored in the muscle cells.
Research shows that after intensely working out, glutamine levels in the body are reduced by as much as 50%. Since the body relies on glutamine as cellular fuel for the immune system, scientific studies have shown that glutamine supplementation can minimize the breakdown of muscle tissue and improve protein metabolism. Its effects on replenishing the body after stress or trauma have been shown in Europe where it is commonly given to patients in hospitals.