Protein is an essential macronutrient in its own right, and paying attention to its source and amount is crucial for those seeking balanced nutrition during physical fitness. How much protein is really necessary? What role does it play in the body? Are there risks associated with too much protein? We've talked with an expert to map the role protein plays for athletes. Sufficient protein, from lean animal and/or plant sources, is crucial for overall good health.
When it comes to protein, the average American typically consumes the Recommended Daily Allowance (RDA), which is 0.8 grams of protein per kilogram of body weight or 3 to 4 grams per 10 pounds. For athletes, though, these recommendations may be higher.
For "endurance athletes"—those whose sport is running or cycling, for example—the typical recommendation is 1.2 to 1.6 grams of protein per kilo of body weight. This number is even higher for "power athletes" like weight lifters, or linemen on a football team. They can be advised to get from 1.4 to 1.6 grams of protein per kilogram.
Optimal protein sources for athletes are lean meats, as well as cottage cheese, egg whites or egg substitutes (to minimize cholesterol intake) and soy products, such as tofu. Greek yogurt, which is strained and thicker than regular yogurt, has a higher protein content per serving than regular yogurt, so that's good, and protein powders, like whey protein, can be pretty convenient as well. Other foods with incomplete but important protein include whole grains and whole grain breads and pastas. Nut and nut butters offer incomplete protein, too, but the calories can really add up, so those interested in weight loss need to be careful.
Protein's relationship to muscle is straightforward: muscle is made of protein. There are 20 amino acids, and 9 of them are essential to meet our protein needs. When muscles are used during exercise they break down, and they need to be rebuilt post-exercise. The body needs protein to do this. This means the athlete needs to consume enough protein to provide for muscle repair.
Athletes also need to make sure they stay in positive nitrogen balance. Protein is the only source of nitrogen in the diet, and while you need nitrogen, too much isn't good for you. Anyone increasing their protein intake needs to drink plenty of fluids so any excess nitrogen can be flushed out.
Protein also plays a significant role in recovery for athletes. Along with carbs, protein supports the resynthesis of glycogen along with the rebuilding and repair of damaged muscle tissue.
As with people trying to lose weight, athletes also benefit from the fact that protein is satiating and makes you feel full longer. That helps anyone stick to a specific diet.
Even athletes can overdo it on the protein front, though. Someone whose intake is in the range of 35 to 40 percent of calories from protein, for example, might also be consuming too much fat and cholesterol, as well as squeezing out other important nutrients in favor of protein. Plus, since muscle is built by tearing muscle fibers during exercise and then rebuilding them during recovery, eating more protein than is used in that process is superfluous.
In general, so long as the person has good kidney function and their fluid intake is high (so they can flush out excess nitrogen), there would be nothing negative about a protein intake at 20-25%; beyond 30% is not well studied.
Dr. Marlia Braun, an outpatient dietitian and sports nutritionist within the UC Davis Health System explains why a higher protein intake for athletes—especially competitive ones—is necessary.