When it comes to the most important meals, we're told everything!

Breakfast, post-workout, before bed, the list goes on.

Our post-workout intake has long been touted as one of the most important, notably the so called half an hour "window of opportunity" after training.

But the reality is that currently, although it's somewhat promising, there's not enough evidence to suggest the 30 minute "window of opportunity" exists FOR SURE.

So let's attempt to answer the question: is the post workout window idealogy a myth?

THE RESEARCH

A recent study (1) looked at protein synthesis over a full 24 hour period, and found it to be the same after 3 hours and again the 24 hour mark.

This would suggest that the meals you're eating both at 3 hours after your workout and a FULL DAY afterwards, are all equally as beneficial to your muscle gains, and there's no magic time frame here.

Protein synthesis has been found to be the same at 3h and 24h after your workouts!

Another study (6) that looked at essential amino acid and carbohydrate intake 1 hour v 3 hours following resistance training, and found no notable difference in leg net amino acid balance.

The post-workout window ideology might have stemmed from one particular study involving elderly subjects, and there response to resistance training (2).

It was discovered that immediate intake of an oral protein, carbohydrate and fat supplement after a workout, was more efficient than 2 hours after a workout.

But we can't sit here and think this applies to all of us, given the elderly absorb protein differently than younger subjects.

To quote from one paper (3) that looked at protein absorption in the elderly: "We have demonstrated that whey protein and casein affect protein gain differently during ageing."

Protein absorption is whole new ball game in the elderly

The other belief behind the "anabolic window" is that insulin sensitivity is increased within a small time frame following resistance training.

The theory is to make the most of the anabolic hormone in this period.

But fresh data (9) reveals that a single resistance training session enhances insulin sensitivity in healthy men, for 24 hours!

Furthermore, a large meta-analysis was done this year on the evidence of post-workout nutrition, and printed in the Journal of the International Society of Sports Nutrition.

The authors noted: "despite the common recommendation to consume protein as soon as possible post-exercise, evidence-based support for this practice is currently lacking."

STUDIES SUPPORTING THE "ANABOLIC WINDOW"

One study (4) took 5 men and 5 women and studied them twice; giving them 10 g protein, 8 g carbohydrate and 3 g fat, 3 hours after a workout, and immediately after a workout.

Protein synthesis in the legs and whole body was far superior right immediately after training, but the problem many had with this study, is that it looked at cardiovascular training on a stationary bike - much different to a resistance training workout that might be undertaken by a most females and males.

I might point out also, that, interestingly, proteolysis (the breaking down of proteins) was unaffected between the two different times.

But more to the point of resistance training, in 1994, there was research (5) that supported administering nutrients immediately after training to 9 experienced male weight lifters.

A protein/carbohydrate supplement yielded better results in terms of protein synthesis immediately after training, but when push came to shove, there was only the TINIEST difference in muscle mass and fat oxidation in those who took the supplement immediately.

But it's still worth pointing out. The suggestion is not that the "anabolic window" is a COMPLETE load of rubbish, but rather that there's NOT enough research to support it, despite the fact it's pedalled by some gym rats as a definite fact.

The anabolic window: not enough SOLID evidence yet to support it. 

I've even heard people say a workout is wasted if you don't get your post-workout shake in within a half an hour.

Now that is a HUGE stretch, and there's just no CONCRETE science to back up such statements at all!

THE PRE-WORKOUT MEAL AND ITS SIGNIFICANCE TO THE POST-WORKOUT MEAL

The other issue with the body of research we have today, is that the pre-workout shake has a huge bearing on the impact and results of the post-workout shake. It's difficult to decipher what effect a post-workout meal/shake can have, given pre-workout shakes have been found (7) to increase resting energy expenditure by 8.5%, 24 hours after training (due to the metabolic cost of protein synthesis).

So is it the PRE workout shake/meal or the POST that is making the difference?

It's VERY hard to examine the "anabolic window" on its own.

One research paper (8) found no significant difference in net muscle protein synthesis, when examining 20 g whey immediately pre-workout, versus 20g whey consumed 1 hour post-exercise.

So could the humble pre-workout intake be more important?

Is there too much importance resting on the shoulders of the anabolic window and the post-workout period?

PRE-WORKOUT INTAKE: THE RESEARCH 

Just 6 grams of essential amino acids taken IMMEDIATELY before training has been shown to elevate blood and muscle amino levels by about 130%, with levels remaining elevated for 2 hours after the session (10).

 

So if you're sucking down some essential amino's RIGHT before the gym - your IMMEDIATE post-workout intake wouldn't have much of an effect at all.

 

The same group of researchers also showed that the ingestion of 20g of whey increases muscular uptake of amino acids to 4.4 times pre-workout levels during the session, with a drop to baseline levels not occurring until 3 hours after training! (11).

 

And the workout of choice? 10 sets of 8 reps on the leg press, which isn't to be sneezed at.

 

The subsequent suggestion here, according to the authors behind the meta-analysis of nutrient timing, printed in the Journal of the International Society of Sports Nutrition this year: "immediate post-exercise protein dosing for the aim of mitigating catabolism seems redundant." 

PRE v POST

As mentioned earlier, it's damn difficult to examine the effects of post-workout intake alone.

 

Another study (12) examined 23 recreational bodybuilders, with pre and post-workout protein consumption found to have significant benefit.

 

Subjects found themselves in either the PRE-POST group (supplement with protein, carbohydrates and creatine) immediately BEFORE and AFTER training, or the MORNING-EVENING group, that had the same supplement but at the MORNING and EVENING times, at least 5 hours outside the training session.

 

Both of the groups performed resistance training style workouts for 10 weeks, with intensity increasing from 70% of their 1 REP MAX to 95% of their 1 REP MAX over the period of time.

 

 

The PRE-POST group finished up with a GREATER increase in lean body mass, and a larger type II fibre area.

 

But the question remains, was it the POST-WORKOUT "window" that did it - or the PRE-WORKOUT intake?!

 

Another study (13) found pre-workout shakes increase resting energy expenditure by 8.5%, 24 hours after training (due to the metabolic cost of protein synthesis).

 

The evidence so far just isn't clear, but one thing certainly seems to be; the humble pre-workout shake is most likely very underrated and should always be taken! 

CONCLUSION 

Always ensure your pre-workout cocktail is ingested before training.

 

Whether it's 15 grams of essential amino acids(14), or around 25-30 grams of whey protein, make sure you're taking it!

 

The benefits for your pre-workout supplementation are quite well supported by science, as opposed to the lack of definite evidence pertaining to the "anabolic window".

 

Consume your post-workout shake 30min - 1hr after training, or even just eat a meal like I prefer to do, and don't stress about being in a catabolic state, as your pre-workout intake will most likely still be hanging around (10,11).

 

So the FINAL verdict?

 

At this stage, I'd be recommending you to NAIL your PRE.......and RELAX on your POST.  

 

 

Stay Fit, Stay Flexed!  

 

 

REFERENCES

 

(1) Tipton KD, Borsheim E, Wolf SE, Sanford AP, Wolfe RR. Acute response of net muscle protein balance reflects 24-h balance after exercise and amino acid ingestion. Am J Physiol Endocrinol Metab. 2003 Jan;284(1):E76-89. Epub 2002 Sep 11.

(2) Engelen MP, De Castro CL, Rutten EP, Wouters EF, Schols AM, Deutz NE. Enhanced anabolic response to milk protein sip feeding in elderly subjects with COPD is associated with a reduced splanchnic extraction of multiple amino acids. Clin Nutr. 2012 Oct;31(5):616-24. doi: 10.1016/j.clnu.2012.04.006. Epub 2012 Jun 6.

(3) Dangin et al. The rate of protein digestion affects protein gain differently during ageing in humans. The Journal of Physiology. June 1, 2003. p549, 635-644.

(4) Levenhagen DK, Gresham JD, Carlson MG, Maron DJ, Borel MJ, Flakoll PJ: Postexercise nutrient intake timing in humans is critical to recovery of leg glucose and protein homeostasis. Am J Physiol Endocrinol Metab 2001, 280(6):E982-93.

(5) Chandler RM, Byrne HK, Petterson JG, Ivy JL. Dietary supplements affect the anabolic hormones after weight training exercise. J Appl Physiol 1994;76:839-845.

(6) Rasmussen BB, Tipton KD, Miller SL, Wolf SE, Wolfe RR: An oral essential amino acid-carbohydrate supplement enhances muscle protein anabolism after resistance exercise. J Appl Physiol 2000, 88(2):386-92.

(7) Hackney KJ, Bruenger AJ, Lemmer JT. Timing protein intake increases energy expenditure 24h after resistance training. Med Sci Sports Exerc. 2010 May;42(5):998-1003. doi: 10.1249/MSS.0b013e3181c12976.

(8) Tipton KD, Elliott TA, Cree MG, Aarsland AA, Sanford AP, Wolfe RR: Stimulation of net muscle protein synthesis by whey protein ingestion before and after exercise. Am J Physiol Endocrinol Metab 2007, 292(1):E71-6.

(9) Koopman R, Manders RJ, Zorenc AH, Hul GB, Kuipers H, Keizer HA, Van Loon LJ. A single session of resistance exercise enhances insulin sensitivity for at least 24 hours in healthy men. Eur J Appl Physiol. 2005 May;94(1-2):180-7. Epub 2005 Mar 11.