BY HUMAN KINETICS
How much protein do you need? How does protein impact performance? Learn more in this episode of Trainer Talk where certified trainers Aaron Patterson, NSCA-CPT, CWPC, CSAC, CTPS and Korey Van Wyk, MS, CSCS, Pn2 discuss the power of protein.
Learn more about how much protein you need in this excerpt from NSCA's Guide to Sport and Exercise Nutrition by the NSCA.
The daily recommended intake (DRI) established nutrient recommendations
with the intent of eliminating malnutrition-based disease. In this regard implementation has been largely successful, but the elimination of disease is not the goal of the athlete. Considering performance and adaptation- based goals, protein needs of the athlete are typically much higher than the DRI, which is set at 0.8 g/kg (0.36 g/lb) (42). Other guidelines are needed for the athlete to optimize performance and adaptation to exercise.
In other circumstances a person may need more protein than the current recommendations. For this reason, the adjusted macronutrient distribution
score (AMDR) has been developed. This measure provides a range for nutrient intake as a percentage of total caloric intake, based on the needs of the individual (31). For protein, the AMDR is 10% to 35% of daily caloric intake (42). The wide range is designed to offer greater flexibility and develop more specific guidelines tailored to the needs of the individual. For example, an athlete who is consuming more total calories will likely need a smaller proportion of this intake to come from protein.
This nutrient is of such importance that some sport dietitians begin to calculate macronutrient distribution by first establishing protein intake and then establishing the needs of the other macronutrients (31). Consistent with the application of the AMDR, a wide range of daily proteins intake can be appropriate for different athletes. In contrast to more traditional methodologies that classify athletes based on aerobic endurance versus strength, and provide static suggestions, a more flexible approach allows greater athlete-centric specificity of nutritional recommendations (32). In this way, nutrition specificity is like training specificity for the athlete. Some important considerations for determining athlete-specific protein
• training age (also known as experience),
• current periodization phase and goals,
• food choices and preferences, and
• total caloric intake.
More experienced athletes, for example, may need less protein than those who are unaccustomed to exercise. Intense peaking phases will likely necessitate greater protein intake than periods during the offseason. Because of the reduced quality of plant-based protein, vegan athletes may need to consume more protein than those with an omnivorous diet. Finally, periods of caloric restriction require the consumption of greater quantities of protein. This common occurrence has such a profound effect on protein metabolism that a more robust discussion is provided (32).
Protein Dose: Acute
The lay media have offered many recommendations for protein intake per meal, but finding a solid understanding of the rationale behind them is difficult. Fundamentally, the reader can apply the nutraceutical effect and understand that the commonly cited 20 g limit is based not on protein digestion or absorption, but on the maximal stimulation of MPS. More specifically, this 20 g dose is the minimum required to cause maximal stimulation of MPS. Doses beyond this point will not further stimulate protein synthesis, but will progressively increase ingested protein breakdown (23, 41). The 20 g ceiling has been found with both whole-egg protein consumption (23) and whey protein (41).
To add further precision to this application, a bodyweight-specific protein dose per meal has been suggested as 0.31 g/kg (0.14 g/lb) to produce maximal stimulation of MPS (24). This quantity falls in line with the 1.4 g/kg (0.64 g/lb) daily dose and the AMDR.
Another factor in considering single-meal dose is the absorption speed of the protein. Those that are absorbed more slowly or consumed within whole-food meals may not be limited to the 20 g quantity, because their goal is to sustain training-induced MPS rather than cause a rapid pulse in blood amino acid levels (38). For this reason, daily protein intake is helpful for establishing per-meal protein quantity.
Protein Dose: Chronic
Chronic or daily protein dosing may be the most important consideration for optimizing the adaptive response from exercise (26). A protein dose of 1.4 to 1.7 g per kilogram body weight per day will be suitable for athletes most of the time (15). To provide some flexibility to account for atypical metabolic circumstances, such as calorie-restricted diets, a dose up to 2 g per kilogram body weight per day is suggested (32), which is consistent with the parameters of the AMDR (31).
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