Branched-chain amino acids, also known as BCAA's, are among three of the nine essential amino acids for humans. Essential amino acids are those that the body cannot synthesize on its own and must get adequate amounts of through dietary sources. BCAA's comprise about 35% of the aminos within muscle tissue. They are isoleucine, leucine, and valine. The name "branched-chain amino acids" comes from the structure of these compounds (see picture). They are the only amino acids that are not degraded in the liver, meaning they head directly into the bloodstream.
Why should I take BCAA's?
To help build and preserve muscle while burning body fat.
When should I take BCAA's?
Before, during, or immediately following your workout.
BCAA's & body fat loss
Recent research has shown that BCAA's can have a positive effect on fat loss. More specifically, they seem to maximize fat loss when one is already on a diet that is geared towards losing fat. In most cases, this means a diet with a reduced carb intake. Research also shows that BCAA's preserve muscle. For this reason, they can and should be used as a supplement during any fat loss program. Whenever on a restricted caloric intake, it is a delicate balance between burning fat while still retaining and building muscle. Your body is forced to find some source of energy to burn. Ideally, this would be your body fat and nothing else. However, what you want to happen and what your body wants to do are not the same thing. When put under pressure or stress, your body kicks into survival mode, and will pull energy from wherever it needs to in order to function. BCAA's help protect and preserve muscle in this situation.
What sets BCAA's apart from other amino acids is how they are metabolized. Unlike most other amino acids, BCAA's are metabolized within muscle tissue, as opposed to the liver, allowing them to be used as a quick energy source when the body needs it. Because the body requires more energy during periods of stress such as training or lifting, there is a significant increase in BCAA metabolism during prolonged exercise. This is why BCAAs' are so effective when taken around workout time.