How important is immediate intake of carbohydrates and protein post exercise?
The nutritional strategy of consuming particular nutrient combinations, primarily protein and carbohydrate in and around an exercise bout, has claimed to produce dramatic improvements in body composition. It has been suggested that the timing of particular nutrients is of higher importance than the total daily intake of nutrients. (1)
The post-exercise period is often considered the most critical part of nutrient timing. The depletion of stored fuels glycogen (carbohydrates) and amino acids (protein) following an intense resistance training session causes damage to muscle fibers causing growth to occur. The nutritional strategy of consuming correct ratios of nutrients during this time starts the rebuilding of damaged tissue and the replenishment of energy reserves. It does so in a super compensated fashion, which enhances both body composition and exercise performance. Researchers have referred to this as the ‘anabolic window of opportunity’ a post training time period that can optimize training related muscular adaptation. (2)
Restoring carbohydrate stores post training is considered an essential component to optimize resistance-training performance. This is relevant to individuals with the typical resistance training protocols, which include high volume (multiple sets) working the same muscle groups. This type of training results in depletion of the majority of local glycogen (carbohydrate) stores.
What if I train 2x per day?
Without question, accelerating glycogen resynthesis is of higher importance to individuals training 2x per day where duration of glycogen depleting activity is limited to less then 8 hours apart. However, if you only train once per day the urgency of glycogen resynthesis is greatly diminished. (2)
What if I’m trying to reduce body fat levels?
In caloric restriction (required to reduce body fat levels) the option of consuming whole foods to obtain your calorie requirements as opposed to using supplementation, (usually in the form of Dextrose), will usually be more appealing to an individuals appetite. When your goal is to maximize the rate of muscle gain, research supports the broader objective of meeting total daily carbohydrate requirements instead of specifically timed doses.
“Which would you prefer a plate of chicken, potatoes and vegetables or a scoop of Whey protein and Dextrose powder?”
What if I train first thing in the morning?
In the case of resistance training prior to eating after sleeping overnight, the practical recommendation is immediate nutrition to fuel the workout, in the form of protein and carbohydrate.
- An individual with the goal of increasing muscular size and/or strength should make a concerted effort to consume a pre-exercise meal 1-2 hours prior to exercise to maximize performance.
- The pre-exercise meal that includes a minimal to moderate high quality protein source taken immediately before the onset of resistance training is capable of sustaining amino acid delivery into the post-exercise period. (3) Given this outcome, immediate post-exercise protein intake seems unnecessary. The next scheduled protein rich meal (whether it comes immediately or 1-2 hours post-exercise) will likely provide the opportunity to maximize recovery and anabolism. (3)
- However, if the previous meal was finished 4-6 hours prior to starting exercise, this interval in nutrient consumption can be considered significant enough to warrant post-exercise intervention, when the goal of muscle retention or growth is crucial.
References and Further Reading
- Lambert, C., Frank, L., & Evans, W. (2004). Macronutrient considerations for the sport of bodybuilding. Sports Med, 34, 317 – 327.
- Aragon, A., & Schoenfeld, B. (2013). Nutrient timing revisited: is there a post-exercise anabolic window? J Int Soc Sports Nutr, 10, 5.
- Tipton, K., Elliott, T., Cree, M., Aarsland, A., Sanford, A., & Wolfe, R. (2007). Stimulation of net muscle protein synthesis by whey protein ingestion before and after exercise. Am J Physiol Endocrinol Metab, 292, E71 – E76.