What is Protein?
The simplest answer that requires no organic chemistry is "the building blocks for...well...everything." Your skin, hair and nails, muscles - it is an important part of every cell of your body. It is considered a macronutrient, which means, like fat and carbohydrates, your body needs a relatively large amount of it daily to continue its functions. Unlike fat and carbs, protein doesn't make an efficient source of energy, though as you'll read on you'll realize that it can be burned for energy.
What are Amino Acids?
Amino acids are basically the building blocks of proteins. One could say when you ingest protein, you deliver amino acids to your body. AA's are in two basic categories, essential and non-essential. By definition, "essential" means your body cannot produce it, and it must be ingested from food. I've always been a little unclear as to the distinction between the two categories to be honest.
Amino Acid Structure: amino group, side chain, and carboxylic group
What is a complete protein?
A complete protein is basically a food source that delivers adequate amounts of the 9 essential amino acids to your body. All meat, fish, eggs, and dairy are complete proteins. Plants are usually incomplete, meaning they need to be combined to create "complimentary" proteins - the full spectrum of the 9 essential aa's through eating combinations of foods. Soy and quinoa are examples of complete plant proteins.
What are the BCAA's?
Branch-chained amino acids are specifically related to the building and repairing of muscle and tissues. You should know these three - leucine, isoleucine, and valine (think acronym LIV). There are also some soft studies that say taking doses of BCAA's can improve performance during an athletic event, though it's tough to say how true this is. The general practice if you believe this would be to take a supplement with BCAA's for long endurance events, like a marathon or long bike ride. Some other studies show that BCAA's inhibit the absorption of tryptophan (another essential amino acid) in the brain. Tryptophan releases serotonin and aids in falling asleep, so over consumption of BCAA's might lead to unrest.
What is Glutamine?
Glutamine is one of the more popular non-essential amino acids, and is often found in recovery drinks or other protein supplements. It is usually associated with minimizing the catabolism of muscle after workouts and even might have some immunity benefits. It is also a very "universal" amino acid, it can act as other essential amino acids once in the body, and is even considered a sort of essential/non-essential hybrid.
How much protein do I need per day?
Protein needs are usually measured in g/kg BW, which means grams of protein per kilogram of body weight. Needs vary per the individual, but to give you the rough estimates using pounds of body weight:
A fairly sedentary person needs .2 - 4g of protein per pound of BW
An active person needs .4 - .7g of protein per pound of BW
A power/strength athlete, or someone wanted to add size needs .7 - 1g of protein per pound of BW
A bodybuilder might go as high as 1.5g of protein per pound of BW
There are some rumors that if you take in too much protein your body can't absorb it all and it will get stored as fat. This might be true, but likely isn't true. Your body is pretty efficient at absorbing protein!
Benefits of High Protein Diets
Proteins keep you full, take a long time to digest, help control blood sugar, and when taken in large portions, you usually eat fewer refined carbs and refined fats, making high protein diets a good choice if you want to lose weight. However, any diet that focuses on one macronutrient can lead to an imbalance - you still need quality carbs and fats to be your healthiest.
Do I need to supplement protein?
You might need to supplement protein if you are having trouble eating enough in your diet and don't have time to prepare foods. I get almost all my protein from fish, chicken, pork, eggs, Shakeology, and greek yogurt. Nuts, beans, and other legumes can provide quality protein as well - with a lot of prep, even a vegan can adequately deliver the needed amount of amino acids to their body. Protein powders can be nice, but are often devoid of other nutrient value (the "micronutrients" - vitamins, minerals, and other phytochemicals present from plant and animal sources) so they really are added calories to your diet as protein, lacking of other nutrition. Protein bars and pre-mixed shakes are generally not efficient choices for protein supplementation - they often have lots of additives, and even high amounts of sugar and saturated fat to make them taste better and increase shelf life. FYI - I don't consider Shakeology a "protein powder" - it's a superfood shake. It does have 15+g of quality protein, but the benefits are beyond just the added protein calories, which is why I use it.
When's the best time to eat protein?
In general the "when" doesn't matter - it's a building block, and it needs to be in your body. However, it might be slightly more beneficial after a workout than before. Most research and empirical evidence shows that 10-20g of protein after a workout in combination with simple carbs will help repair and rebuild muscle tissue. Any more than 20g might be wasted calories, and note that the carb component is essential in that post-workout window to replenish glycogen stores in the muscles. The classic "chug 50g of whey protein after lifting" isn't as necessary as you think.
Is it possible to burn muscle by working out too hard?
Actually - yes. The more intense your workout, the higher the amount of amino acids that are used for fuel. Now, I've seen graphs that show the amount of fat, carbs, and amino acids being burned at different intensity levels, and even when you are at max effort, maybe only about 5% of the energy being burned is amino acids, so it's not a huge impact. But this is one of the reasons that active people need more protein, to replenish those amino acids that might be burned during a workout. You shouldn't be scared to workout hard in fear of breaking down muscle, but if you aren't eating enough, particularly enough protein, and are doing a program like P90X or Insanity, you might not tone up and gain the muscle you want because of a lack in proper nutrition.
Anything Else I Need to Know?