What to Eat: Protein

Q: Why is protein so important?
(This is especially relevant for those of you who manage to fit some regular exercise into your schedules – congrats, by the way!)

A: Every cell in the body contains protein; it is the main component of muscle, bone, skin, hair, and pretty much every other tissue and organ.  Protein makes up the enzymes that power chemical reactions in the body, and it forms hemoglobin – the compound that carries oxygen in your blood.  Overall, the human body is comprised of at least 10,000 different proteins, all functioning to create and maintain all the tissues and systems that make you who you are.

A molecule of protein is made up of amino acids.  Just like simple sugar molecules can be linked together to form various types of carbohydrates, different amino acids can be linked together to form various types of proteins.  This is why amino acids have been called the “building blocks” of proteins (if you can remember back to freshman biology…).

There are 20 amino acids that can be arranged to make proteins.  Their precise order in the protein chain, along with the 3-dimensional structure of the chain (basically, how the chain folds up, origami-style), determines the specific function of the protein.  Simply by varying the sequence of amino acids and the 3-D structure, 20 amino acids are able to form over 10,000 unique proteins!

Every organism is able to synthesize, or produce, some of the amino acids it needs – but most can’t synthesize all 20 of them.  In humans, there are eight* amino acids that our bodies can’t produce.  However, we must have all 20 to create the specific proteins our bodies need to grow and function properly.   Thus, these eight are called “essential amino acids”, and we must consume them in our diet on a daily basis in order for our bodies can continue to build muscle, tissue and enzymes.

You can see how important this is when you are working out regularly.  After you strength train, your body needs to repair any muscle damage (just minor damage – completely normal and necessary) and refuel your energy stores.  It does this rebuilding by linking amino acids.  If you’ve trained with me, you’ve heard me talk over and over about the importance of consuming protein after your workout.  You need to consume those amino acids (especially the eight essential ones) to make sure your body is able to repair itself and recover quickly from the stress of the workout.  Pairing this protein with a good source of carbohydrate (like the combination of low-fat cottage cheese and fresh berries) ensures that you’ll be getting all the nutrients your body needs to recover quickly from the workout session and rebuild itself even stronger.

* Some sources quote nine or even ten essential amino acids.  There are several “semi-essential” amino acids in addition to the eight mentioned above, which sometimes get grouped together.  The semi-essential, or conditionally essential, amino acids can be synthesized internally if the conditions are right.  However, the eight essential amino acids for humans are phenylalanine, valine, threonine, tryptophan, isoleucine, methionine, leucine, and lysine.

Read more on protein:

Your Muscles Need Protein