Something which is endlessly discussed on bodybuilding forums is how nutrition should be tailored to fit our training needs. In particular, the period prior, during, and after training is the subject of much discussion and critical analysis, with opinions ranging from the post-workout window being of vital importance to those who argue overall macronutrient intake is all that matters with issues of nutrient timing being of relatively little consequence.

When we look at the way elite athletes have typically approached nutrition, there is a general belief in the importance of consuming carbohydrates, in particular after training to help replenish glycogen stores, while bodybuilders will prioritise protein intake after a workout to maximise the anabolic response to training. There has been generally less attention paid to the food consumed prior to the workouts so a study (1) which compared two different protocols is a helpful addition to the canon of work in this area.

 

Objective: To determine whether consumption of a mixed essential amino acid-carbohydrate supplement (EAC) containing 6g of EAA and 35g of carbs causes a differential response depending on whether it is consumed before or after a strength training workout.

 

Methods: Six healthy subjects took part in the trial and, in a randomised trial consumed the supplement either before (PRE) or after (POST) their training session. Various physiological measures were taken to determine amino acid concentrations and amino acid uptake into the leg muscles.

 

Results: Amino acid uptake in the working leg muscle increased during exercises and remained at an elevated level for two hours after the exercise session during both trials. The delivery of amino acids was significantly greater in PRE than in POST both during the exercise bout and in the first hour after exercise. Total net phenylalanine uptake was greater during the PRE rather than POST trial. Phenylalanine disappearance rate, used as a proxy for muscle protein synthesis from blood amino acids, increased after EAC supplementation in both treatments.

 

Conclusion: The researchers concluded that consuming the supplement before training led to greater muscle protein synthesis as a result of greater uptake of amino acids to the musculature.

 

Our Comments

If we dig into the raw data presented by this study, it shows that when the EAC supplement was taken prior to training, 42% of the amino acids in the drink were taken up into the muscle versus only 16% when the drink was consumed after training. This means more than twice as many amino acids are taken up if we eat before a meal. So much for the importance of post-workout nutrition you might say?

As ever, it is not so simple. One of the major drawbacks with studies is that they typically use subjects who have completed an overnight fast so that the data is not skewed by previous consumption of nutrients and it is easier to analyse different treatment regimens more accurately.

Unfortunately, very few strength athletes will train in a fasted state making it difficult to draw conclusions from this single study. Would the same result have occurred if we compared two trials where training took place in the evening and the trials were split into a group who consumed their EAC supplement right before their training or after training but where both had already consumed several meals during the day?

When we look at studies performed on fasted subjects, we also see an increase in fat oxidation and anabolic signalling which is why this type of training is becoming quite popular, especially among the adherents of intermittent fasting who cite it as a key factor in that diet’s success. While we do not accept fasted training is necessarily better (read our post on fasted cardio), it does show that it is not always as simple as measuring something like amino acid uptake in isolation without considering how a meal will affect the body at large.

Finally, the actual quantity of amino acids provided in this study was not really high enough in our view. The average bodybuilder is going to require more than a six gram dose of essential amino acids before training, especially if, as in this case, no other protein was ingested earlier in the day.

Future research would ideally compare a pre versus post-workout meal but do so after a standardised dietary intake during the day. In our opinion, if someone’s last meal was a large one at midday and they are training at 2PM, a small EAC supplement before training would likely not show the same magnitude of benefit compared to the same supplement after training. While it would not do harm, a much better way of increasing performance during the ensuing workout would be achieved via the use of a dedicated pre-workout supplement which, by enhancing energy, focus, motivation and nutrients to enhance performance, would make a bigger difference by far.

 

Author: Reggie Johal

 

Further Reading

Post Workout Nutrition
Meal Frequency

 

References

1. Tipton, KD et.al (2000): Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise.

© 2012, Reggie Johal. All rights reserved.