Protein is an essential nutrient providing four calories per gram that is responsible for a host of activities in the body. It is a component of every cell, and approximately 17 per cent of body weight (in the form of lean tissue) comes from protein. Protein is crucial to the regulation and maintenance of the body and plays a role in blood clotting, fluid balance (hydration), hormone and enzyme production, and cell repair. So it’s no wonder that you need protein every day, though many of us are led to believe we need a whole lot more than we truly do.
So where exactly does protein come from, and what are the best sources? As you might already know, protein is made up of amino acids. Of the 20 amino acids used in the body, nine are essential, which means that your diet must provide them because your body can’t make them (similar to many other nutrients). Eleven amino acids are non-essential, which means your body can make them using other amino acids. If a protein is “complete,” it contains all of the nine essential amino acids in sufficient amounts. Some protein sources are naturally complete, and those include animal proteins (steak, fish, pork, etc), dairy proteins (casein, whey, cottage cheese, yogurt), and a handful of vegetable proteins (soy and quinoa).
Incomplete proteins, on the other hand, don’t contain all nine of the essential amino acids, but if you vary your sources of incomplete proteins and mix these sources up throughout the day, you’re likely to take in enough amino acids to meet your needs. An example of combining incomplete proteins to include all nine essential amino acids (known as a complementary protein) is red beans and rice. When mixed together, the legumes and grain contain the amino acids you need to repair tissue and stave off injury. But don’t sweat it if this is too much meal planning for you; you actually don’t even have to combine complementary proteins like legumes and grains at every meal. If you accumulate each source throughout the day, you’ll be fine.
But you might be wondering how much protein you actually need. And you’re right to wonder; with so much press given to protein these days, you’re likely convinced you need a lot if you want to build muscle, or stay energised, or lose weight, or fight off disease, or whatever.
While you do need protein each and every day, it’s likely you’re already taking in enough. The current recommended daily allowance (RDA) for protein is 0.36 grams/lb, and that’s for all adults.
Since you're an endurance athlete and not an armchair athlete, you need more than the average Joe. This additional protein will help replace the protein you break down during exercise, help you build lean tissue and help your muscles recover from taxing workouts so that you’re primed for the next time you hit the road.
Protein may not be a magic bullet - increased supplementation has not been found to automatically improve performance - but if your intake is low, you may start to feel fatigued, lose muscle mass, become rundown and increase your risk of injury.
You can prevent much of this by aiming for an intake of at least 0.55-0.77 grams/lb (aim for the upper end of the spectrum during times of heavy training and racing). Which means that if you weigh 130 pounds, you’ll want to aim for approximately 72-100 grams of protein a day; a 195-pound runner will need to aim for approximately 107-123 grams/day.
Protein is a hot-ticket item these days, so thanks to clever packaging and marketing, you’re likely to know exactly how much protein is in your food. But some sources, like egg whites, are more biologically available than others, like wheat bread. And when it comes to supplemental protein sources, such as protein shakes, the quality is all over the place. When planning your daily intake, it’s best to aim for a variety of sources. When boosting your intake with a protein shake, choose whey protein, a blend of protein sources (like whey and casein), or, if opting for a vegetarian source, a complete protein like soy or a blend of soy and other vegetarian sources.