Here is part 2 of the post on Eating for Performance from our resident Nutrition writer Jen. To read part 1 click here.
From the ancient Greek coaches of Olympians to today’s elite athletes, protein has been considered a key nutrient for success. The mentality was more protein equals more muscle growth and therefore more strength. For the same duration, the controversy over its importance has also been present. Protein and amino acid supplement have become a billion dollar industry. Strength/speed/power athletes were recommended 1.2–1.7g/kg per day while endurance athletes 1.2–1.4g/day; these recommendations are higher than the US recommended daily allowance, which is 0.8g/kg.
Despite the growing protein supplement industry, surveys of westernized athletes consuming adequate calories consistently show sufficient protein intakes with diet alone. Furthermore, excess protein can be detrimental to performance by replacing carbohydrates in the diet, resulting in less stored glycogen. This is heightened even more while on a calorie restricted diet. If muscle growth is a goal, as opposed to better performance, higher protein intake may be beneficial; however there is minimal convincing research showing that high protein intakes (e.g. 2-3g/kg) are necessary.
So is there any value for protein supplements in terms of performance? The answer is yes, but not for the same reason many people think (e.g. more protein=more strength). Emerging research is showing that nutrient timing is more important than overall protein intake. Although some studies have shown protein intake is important within up to 3 hours after workout, more recent studies are showing greater benefits from more immediate consumption of a higher quality protein.
Some athletes might find meals immediately post workout inconvenient so protein supplements may be a beneficial alternative. Keep in mind, the quality of these supplements should be assessed (e.g. additives, source). The best dose to promote muscle protein synthesis seems to be about 20g (variable with body weight); any higher and the protein is often just oxidized and not used.
The warrior protein blend from Sunwarrior is my go-to supplement and is a great option for vegans and omnivores alike. Take home point: the timing of protein consumption post-exercise, with high-quality protein, may be a better predictor of muscle mass and strength gains than an overall higher protein intake.
With all of the science in mind, here is my guide to eating for performance!
Pre-workout: Low glycemic (GI) (e.g. Sunwarrior Activated Barley) and high GI (e.g. banana) carbohydrates would be suitable to consume before a workout to provide both immediate and sustained energy. More recently, studies have indicated that pre-workout ingestion of protein along with carbs is advantageous for enhancing training adaptations and decreasing muscle damage. The optimal protein and carbohydrate content in a pre-workout meal depends on what your workout entails, but general guidelines recommend 1–2g of carbs/kg and 0.15–0.25g of protein/kg three to four hours before a workout.
During: As exercise increases over 60 minutes, dietary carbohydrates become more important to maintain blood glucose and muscle glycogen. The recommended intake for carbohydrates during a workout is 30–60g/hr. The addition of protein to carbohydrates, at a ratio of about 4:1 carbs to protein, has been shown to increase endurance performance even more in both the short and long term.
Post-exercise: A mix of a high quality protein (15–25 grams) and carbohydrates post-workout will maximize glycogen stores and enhance recovery. Whether you choose a supplement or food source is up to you, but keep in mind, protein and carbs should be ingested quickly after a workout—preferably within the first 45 minutes.
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Kerksick, C., Harvey, T., Stout, J., Campbell, B., Wilborn, C., Kreider, R., Kalman, D., Ziegenfuss, T., Lopez, H., Landis, J., Ivy, J., & Antonio, J. (2008) International Society of Sports Nutrition position stand: nutrient timing. Journal of the International Society of Sports Nutrition, 5:17.
Phillips S. (2012) Dietary protein requirements and adaptive advantages in athletes. British Journal of Nutrition 108:S158–S167.
Stellingwerff T, Maughan R, Burke L. (2011): Nutrition for power sports: Middle distance running, track cycling, rowing, canoeing/kayaking, and swimming, Journal of Sports Sciences, 29:sup1, S79-S89.