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Race Fueling

Everything An Athlete Needs To Know About Protein

Your questions about this essential macronutrient, answered by Lauren Antonucci, R.D.

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Your questions about this essential macronutrient, answered by Lauren Antonucci, R.D.

I have received several reader questions regarding protein—optimal daily intake, best sources, timing, etc.—so I’m taking this chance to tell you everything an athlete needs to know about protein.

First the basics: Proteins are nitrogen-containing foods that contain different combinations of 20 amino acids. Nine of those amino acids are considered essential, meaning that our bodies cannot make them and we therefore need to consume them in foods on a regular basis. Protein intake is critical for muscle repair and synthesis as well as production of hormones, enzymes and hemoglobin, and contributes greatly to satiety (feeling of fullness) and immune function.

A triathlete’s daily protein needs are higher than the USDA’s recommendation of 0.8 grams per kilogram per day. Most of us likely need 1.2–1.6 grams of protein per kilogram per day. This equals 65–83 grams for a 120-pound triathlete and 87–116 grams for a 160-pound triathlete. Inadequate total protein intake could lead to muscle breakdown, poor recovery, increased injury rate and compromised immune function.

Pre-workout intake of protein can help spare muscle glycogen during exercise. Aim for 8–20 grams of protein 1–2 hours before training sessions along with your usual carbohydrate fuel.

During endurance exercise lasting more than two hours, studies support the intake of protein (along with carbohydrate) to help preserve muscle. During endurance exercise, your energy expenditure can be made of 1–6 percent protein, and up to 10–15 percent in some instances. Taking in adequate carbohydrate along with 6–8 grams of whey protein per hour will maximize protein sparing and muscle breakdown.

Post-training, you should aim for 15–20 grams of protein to help support muscle repair and synthesis, and support immune function. Aim to consume this within the first 30-minute “recovery window,” and also include carbs to help replenish glycogen (the carbs also cause insulin to be secreted, which helps your body uptake the needed amino acids from your protein).

How much is too much? The absorption rate of protein from the GI tract varies with type of protein eaten but reaches a max of 8–10 grams per hour. Also, excessive protein intake that exceeds the liver’s ability to convert excess nitrogen to urea stresses the body and can lead to increases in ammonia and insulin, as well as nausea, diarrhea and calcium loss, and increases overall fluid needs. Finally, when protein intake exceeds need, it is likely that other nutritious foods—and therefore critical nutrients, vitamins and minerals—are being “crowded out” and deficiencies may result.

So as with most things, adequate protein intake is critical to overall health, weight control and athletic performance, but more is not always better. If you are unsure whether your current protein intake is meeting your needs, find a certified sports dietitian to ensure your attention to nutrition and training efforts pays off!

RELATED: 4 Protein-Rich Snacks

Common Protein Sources

Eggs
6–7 grams each

Greek Yogurt
13–16 grams per 5 ounces

Red Meat
20–25 grams per 3 ounces

Tofu
6 grams per 3 ounces

Low-Fat Milk
8 grams per cup

Cooked Beans
8–9 grams per half cup

RELATED: Tasty Meatless Protein Options

Lauren Antonucci is a board-certified specialist in sports dietetics, three-time Ironman finisher and the founding director of Nutrition Energy in New York City.