In a recent blog, I discussed the calculation of the total amount of protein intake for athletes.  Another important factor is the timing of protein intake, especially in relation to workouts. This question really involves the consumption of two nutrients -- primarily protein and carbohydrate -- in and around an exercise session and are guided by the questions:

• What should I consume before I exercise?
• What should I consume after I exercise?
• What should the meal consist of?

It has been suggested that nutrient timing strategies can produce dramatic improvements in body composition, particularly with respect to increases in muscle mass [Ivy & Portman, 2004] or that the timing of meals, in regards to workouts,  may be even more important than the absolute daily intake of nutrients [Candow et al., 2008]. 

Nutrient Window
Researchers have suggested that a window of opportunity (i.e., nutrient window) may exist to optimize nutrient intake in assisting in training-related muscular adaptations as well as muscle repair [Aargon & Schoenfeld, 2013]. However, the research supporting this idea is confusing, as some research shows benefits of nutrient timing while others have shown little to no benefit [Aargon & Schoenfeld, 2013]. There are a couple of reasons for these disparate results. 

One reason is that much of the research in this area is often conducted in untrained populations. A second reason is that most of the research to date has been conducted in individuals in the fasted state.  Both of these issues can create different results than might be seen in trained athletes. Finally, most of the research to date in this area have only looked at the question of nutrient timing regarding a single bout of exercise compared to chronic training.  Although results from a single bout of exercise have been generally positive, the results of chronic studies in this area have yielded equivocal results [Aargon & Schoenfeld, 2013]. 

Practical Views on Protein Intake 
Although more research into the nutrient window is still needed, there are some practical ideas that can be implemented in combining workouts with post-workout intake.  For starters, a high-quality protein dosed at 0.4–0.5 gram of protein per kilogram of lean muscle mass prior to and following workouts is a safe general guideline. The use of lean muscle mass instead of total body weight again reflects the idea of calculating intake from the tissue that utilizes protein.  

For example, an 80 kilograms athlete with an 8% body fat would have 74 kilograms of fat-free mass.  Using 0.4-0.5 grams of protein per kilogram of lean muscle mass, this individual should consume between 30–37 grams protein in both the pre- and post-exercise meal. Exceeding this would have minimal detriment, if any, whereas significantly under-shooting or neglecting it altogether would not maximize the anabolic response.

In addition to the amount of protein needed, the timing of ingestion of the protein is also key.  Pre- and post-workout meals should not be separated by more than 3–4 hours [Aargon & Schoenfeld, 2013].  For example, if an athlete does a 60-minute resistance training bout they have 90-minute feeding windows on both sides of the workout. Workouts exceeding typical workout durations (>60 minutes) might want to shift training sessions closer to the pre- or post-exercise meal; however, this will ultimately be dictated by personal preference, tolerance, and lifestyle/scheduling constraints.

Practical Views on Carbohydrate Intake
Even more so than with protein, research on carbohydrate dosage and timing relative to resistance training can be confusing [Aargon & Schoenfeld, 2013].  It is important to note that carbohydrate dosage and timing relative to a workout is of greater concern in endurance-trained athletes than in athletes concerned about increase in muscle strength and/or muscle hypertrophy. Future blogs will address carbohydrate intake in endurance-trained athletes.  For our resistance-trained athletes, a basic recommendation for pre- and post-exercise carbohydrate doses is that carbohydrate should match or exceed the amounts of protein consumed in their pre-and post-exercise meals [Aargon & Schoenfeld, 2013]. 

Bottom Line  
Although the idea of a nutrient window is still somewhat controversial, there are some practical guidelines for optimal performance. The bottom line is that the optimal protein pre-and post-workout intake is important for athletes. The use of lean muscle mass to calculate protein intake can provide athletes and training staff with a method to determine the correct protein quantity.

References

Aragon AA, Schoenfeld BJ. Nutrient timing revisited: is there a post-exercise anabolic window, Journal of the International Society of Sports Nutrition 2013, 10:5 http://www.jissn.com/content/10/1/5

Candow DG, Chilibeck PD: Timing of creatine or protein supplementation and resistance training in the elderly. Appl Physiol Nutr Metab 2008, 33(1):184–90.

Ivy J, Portman R: Nutrient Timing: The Future of Sports Nutrition. North Bergen, NJ: Basic Health Publications; 2004.
 

About the Author: Donald Dengel, Ph.D., is a Professor in the School of Kinesiology at the University of Minnesota and is a co-founder of Dexalytics. He serves as the Director of the Laboratory of Integrative Human Physiology, which provides clinical vascular, metabolic, exercise and body composition testing for researchers across the University of Minnesota.