Protein
Protein is another macronutrient of concern because of the many misconceptions regarding amount and type of protein to be consumed for exercise. One study found that 43% of female athletes incorrectly believe that protein is the main energy source for muscles and 34% believe that protein supplements are necessary (18). Similar to carbohydrates, protein requirements are not being met by many athletes. A study conducted frequency analyses that showed 50% of participants (NCAA Division I female collegiate athletes) failed to meet the minimum protein recommendation (1.2 g/kg/day) (8). Furthermore, vegetarian female athletes may be at risk for inadequate protein intake as vegetarian diets generally contain less protein than omnivorous diets (21).
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A study showed 50% of participants (NCAA Division I female collegiate athletes) failed to meet the minimum protein recommendation (1.2 g/kg/day) (8). |
Food Sources of Protein
Why Protein is Important for Female Distance Runners
Most people think of resistance exercise in terms of how to build muscle. However, aerobic exercise can increase muscle protein synthesis (MPS), although the response is smaller compared to resistance exercise. More specifically, high intensity/high volume resistance exercise can stimulate muscle protein rates for at least 2 days afterwards whereas lower intensity aerobic exercise increases MPS for only 2 to 3 hours afterwards (17). Additionally, from a caloric standpoint, aerobic exercise generally burns more calories than resistance exercise and so it is important that energy needs are met after aerobic exercise to ensure that dietary protein is being used for MPS and no being oxidized to meet energy needs. |
Minimum Daily Protein Requirements
The RDA, which is defined as the “average daily nutrient intake level sufficient to meet the nutrient requirements of nearly all (97 to 98 percent) of healthy individuals” (13) for protein for adults is 0.8 grams of protein per kilogram body weight. The Joint Position Paper on Nutrition and Athletic Performance includes a recommendation for protein intakes that range from 1.2 to 1.7 g/kg/day and at least 12 to 15% of energy from protein for healthy athletes.
See a sample one-day menu here.
During Exercise Protein Recommendations
Research has produced conflicting evidence and it seems that coingestion of protein with carbs during endurance exercise is not beneficial to performance. However, some studies suggest performance benefits when protein is consumed with carbs during endurance exercise. For example, one study found decreased protein breakdown when fat-free milk was provided to runners during a 1-hour run (1).
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Research has produced conflicting evidence and it seems that coingestion of protein with carbs during endurance exercise is not beneficial to performance. |
Pre/Post-Exercise (Recovery) Protein Recommendations
Consuming protein prior to exercise has not been as well studied as consuming protein after exercise and the results remain unclear as to whether or not this is beneficial.
Eating post-exercise is important for positive net protein balance (consuming more protein than your body is breaking down) and eliciting an adaptation (muscle hypertrophy, strength, increases in oxidation capacity) (17). Data suggests that consuming high-quality protein within the first 2 hours after training is fundamental to maximizing MPS. The timing of protein intake immediately after exercise seems to be important because this is when protein synthesis is stimulated to the greater extent; however, the postexercise "window of anabolic opportunity" is greater than what is perhaps commonly believed (at least 24 hours after exercise) (17). General recommendation: 10-20 grams of protein within 30 minutes after exercise. |
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For a more comprehensive list of protein content of selected foods, Click here
For a more comprehensive list of protein, fat, and carbohydrate content of selected foods, Click here
For a more comprehensive list of protein, fat, and carbohydrate content of selected foods, Click here
Protein Supplements
You can download and listen to this short presentation explaining protein supplements including types of protein supplements and how to use them. (Once you download the presentation, go to the Slide Show tab and click Play from Start to enjoy the audio version of the presentation).
Vegetarian/Vegan Protein Requirements/Challenges
Vegetarian diets generally contain less protein than omnivorous diets. Additionally, the amount of essential amino acids may be lower in plant foods compared to animal foods and the bioavailability (how well your body absorbs) of amino acids from plant-based foods appears to be lower than animal-based foods. A common recommendation for vegetarian athletes is to consume 10 percent more protein than nonvegetarians, or 1.1 to 2.2 g/kg/day (4).
HOWEVER, most athletes can, and do, get adequate amounts of protein on a plant-based diet and, assuming the amount and timing of protein intake is appropriate and energy intake is sufficient, athletic performance will not suffer (2). |
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