Vegetarianism is on the rise among teenage girls according to a recent study. The ethics of an omnivore with canine teeth specifically designed for eating meat avoiding a portion of their natural food supply will be left for another discussion. From a health standpoint, eating protein is pretty crucial. Side effects of protein malnutrition, known as Kwashiorkor (that’s a mouthfull isn’t it?), include fatigue, irritability, lethargy, loss of muscle mass, swelling, decreased immunity, dermatitis, thinning hair, and in extreme cases coma or even death.
So why is protein so important? Proteins break down into Amino Acids. Your body needs 22 Amino Acids to survive, and can only manufacture 14 of them. The remaining 8 are known as “essential Amino Acids”. The critical ones are: leucine, isoleucine, valine, threonine, methionine, phenylalanine, tryptophan, and lysine. Animal sources contain complete proteins, which means they have all 8 essential amino acids, and are considered higher quality than plant proteins which do not. Animal protein sources are meat and dairy products such as beef, chicken, fish, eggs, milk, butter, cheese etc. Plants have only incomplete protein profiles, however by careful combinations you can achieve full nutrition (with difficulty). Plants can be broken down into four groups, eating one item from group one, and one item from any of the other groups will result in a complete protein intake.
Group 1: Breads, Cereals, Grains (Barley, Oats, Pasta)
Group 2: Legumes (beans, peas, lentils, peanuts, sprouts, soy*)
Group 3: Vegetables (leafy greens, broccoli)
Group 4: Nuts and seeds
*Soy contains phytoestrogens and isoflavones which make it inadvisable to use as a protein source. Further details on this issue will be discussed in another article.
The next question that comes to mind, is “how much is enough?”. Scientists measure protein utilization in the body through your nitrogen balance. Your body excretes nitrogen daily, which is replaced when you consume proteins. If you have a negative balance then you’ll slowly lose muscle mass, which is generally considered a “bad thing”. Most scientific studies done on the subject use either sedentary individuals or college athletes. Generally 0.4 grams per pound of bodyweight is considered the minimum for a sedentary individual to retain lean body mass. For an athlete, or someone who works out with weights (which you should be if you’re trying to lose weight, but we’ll discuss that later) the minimum amount is around 0.8 grams per pound of bodyweight.
Is the minimum amount the optimal amount? It turns out that the answer to this question is no. Positive nitrogen balance has a positive correlation with effective weight loss. (That means they tend to go together) The optimal amount is somewhat under debate, but is generally accepted to be in the range between 0.8g/lb and 1.5g/lb, with the general consensus being that individuals interested in fitness should consume at least 1.0 gram of protein per pound of bodyweight per day. More is often beneficial, but anything over 1.5g/lb is not particularly useful unless you’re taking steroids, as your body just won’t be able to make use of enough of it. Steroids are not recommended as they’re both illegal, and have serious side effects which make them hard on your health, especially when used incorrectly.
For overweight individuals, using bodyweight as an indicator can often lead to higher than required protein intakes. In cases where the subject is more than 25lbs overweight, a good number is 1.25 grams per pound of lean body mass instead of the more normal 1g/lb figure. This number tends to work well for in shape individuals as well. If you don’t know how to figure our your lean body mass, just use the 1g/lb figure for now, and we’ll discuss that issue in more detail later.
