1 gram of protein is equal to 4 calories - first and foremost
Protein is the building block of all the tissue in the body including hair, nails, skin and muscle. As it relates to exercise, protein provides the body with the material it needs to repair damaged muscle tissue.
By reaching the necessary amounts of protein intake for your body you can build and maintain muscle as well as lose fat. In fact, your body burns more calories digesting protein than it does for carbs or fat. Not only that, protein helps you feel fuller longer!
Exercise causes tiny tears to the muscle. The body treats these tears as injuries and repairs them during rest. In addition to rest, the repair process requires nutrients such as: vitamins, minerals, fats, carbs and proteins. The repair process makes you bigger, stronger and faster.
Protein is made up of amino acids. There are two types of amino acids; some the body can produce (non-essential amino acids) and others that need to be ingested (essential amino acids). There are nine essential amino acids (isoleucine, valine, leucine, tryptophan, threonine, methionine, arginine, lysine, histidine) that must be provided to the body through proper nutrition.
The recommended daily allowance is 0.8g/kg (0.4g/lb) of body weight (so about 80g of protein for a 200 pound person) - which can easily be reached through whole protein sources at each meal. However, athletes need a bit more protein per day, usually about 1.4-1.8g/kg if you are strength training or 1.2-1.4g/kg if you are endurance training. This extra requirement is often met through a supplemental protein shake either just before or right after a workout.
Urban legends have spread about the consumption of protein. It is often touted that too much protein can damage your kidneys, and while this is possible in severe excess, studies have shown that elevated protein intake under 2.8g/kg does not impair kidney function. Just as protein intake does not cause renal failure, it also does not cause weight gain (unless you increase your caloric intake).
The best sources of protein is through whole foods such as red meats, poultry, fish, dairy, eggs and nuts. If you are on a budget, here is a list of cheap protein sources:
- Canned Tuna - 40g of protein per can, if you eat 1 can per day or less your mercury intake should be within normal limits. Watch out, however for BPA.
- Whole Eggs - 7g of protein per egg. Don't throw the yolk away! Dietary cholesterol doesn't affect blood cholesterol in the ways previously claimed.
- Whey - 24g of protein per 30g serving
- Ground beef - 25g of protein per 100g of ground beef. You can reduce the amount of fat present by rinsing your ground beef first.
- Milk - 30g of protein per liter of milk. This is great if you can find raw milk in your area, but shy away from milk as a protein source if you are aiming to lose weight.
- Chicken breast - 25g of protein per 100g of chicken
Soy protein is one of the only plant based protein sources considered to be a "complete" protein source. Soy protein is found in soy isolate, tofu, soybeans, miso and soy milk and the clear winner if you are vegan or vegetarian.
Whey is also a "complete" protein derived from animals. Whey is absorbed quickly in the body and has been shown to help build muscle and increase strength. In addition, whey protein helps reduce oxidative stress and has the ability to
Looking at the numbers, whey protein has an efficiency ratio of 3.2, a biological value of 104, 92% protein utilization and 100% digestability compared to an efficency ratio of 2.2, biological value of 74, 61% utilization and 100% digestability for soy protein. This makes whey protein a clear winner for anyone other than vegetarians and vegans. Check out the table below to see the breakdowns for other protein sources as well.
That wraps up our chat on proteins, next up is carbs!