I've not got the time to type it out in my own words, Alan Aragon explains it pretty well while school a typical fourm bro
The postexercise "anabolic window" is a highly misused & abused concept.
Preworkout nutrition all but cancels the urgency, unless you're an endurance athlete with multiple glycogen-depleting events in a single day. Getting down to brass tacks, a relatively recent study (Power et al. 2009) showed that a 45g dose of whey protein isolate takes appx 50 minutes to cause blood AA levels to peak. Resulting insulin levels, which peaked at 40 minutes after ingestion, remained at elevations known to max out the inhibition of muscle protein breakdown (15-30 mU/L) for 120 minutes after ingestion. This dose takes 3 hours for insulin & AA levels to return to baseline from the point of ingestion. The inclusion of carbs to this dose would cause AA & insulin levels to peak higher & stay elevated above baseline even longer.
So much for the anabolic peephole & the urgency to down AAs during your weight training workout; they are already seeping into circulation (& will continue to do so after your training bout is done). Even in the event that a preworkout meal is skipped, the anabolic effect of the postworkout meal is increased as a supercompensatory response (Deldicque et al, 2010). Moving on, another recent study (Staples et al, 2010) found that a substantial dose of carbohydrate (50g maltodextrin) added to 25g whey protein was unable to further increase postexercise net muscle protein balance compared to the protein dose without carbs. Again, this is not to say that adding carbs at this point is counterproductive, but it certainly doesn't support the idea that you must get your lightning-fast postexercise carb orgy for optimal results.
To add to this... Why has the majority of longer-term research failed to show any meaningful differences in nutrient timing relative to the resistance training bout? It's likely because the body is smarter than we give it credit for. Most people don't know that as a result of a single training bout, the receptivity of muscle to protein dosing can persist for at least 24 hours:
Enhanced amino acid sensitivity of myofibrillar pr... [J Nutr. 2011] - PubMed result
More from earlier in the thread:
Here's what you're not seeming to grasp: the "windows" for taking advantage of nutrient timing are not little peepholes. They're more like bay windows of a mansion. You're ignoring just how long the anabolic effects are of a typical mixed meal. Depending on the size of a meal, it takes a good 1-2 hours for circulating substrate levels to peak, and it takes a good 3-6 hours (or more) for everythng to drop back down to baseline.
You're also ignoring the fact that the anabolic effects of a meal are maxed out at much lower levels than typical meals drive insulin & amino acids up to. Furthermore, you're also ignoring the body's ability of anabolic (& fat-oxidative) supercompensation when forced to work in the absence of fuels. So, metaphorically speaking, our physiology basically has the universe mapped out and you're thinking it needs to be taught addition & subtraction.
Properly done preworkout nutrition EASILY elevates insulin above and beyond the maximal threshold seen to inhibit muscle protein breakdown. This insulin elevation resulting from the preworkout meal can persist long after your resistance training bout is done. Therefore, thinking you need to spike anything is only the result of neglecting your preworkout nutrition"
There's no need for quickly absorbed carbs postworkout unless you fulfill all of the following 3 criteria: 1) you have NOT ingested any pre or mid-training carbs, 2) you train to complete glycogen depletion, 3) you're forced to exhustively train those same glycogen-depleted muscles again within the same day.
When speaking of nutrition for improving body composition or training performance, it's crucial to realize there's an underlying hierarchy of importance. At the top of the hierarchy is total amount of the macronutrients by the end of the day. Distantly below that is the precise timing of those nutrients. With very few exceptions, athletes and active individuals eat multiple times per day. Thus, the majority of their day is spent in the postprandial (fed) rather than a post-absorptive (fasted) state. The vast majority of nutrient timing studies have been done on overnight-fasted subjects put through glycogen depletion protocols, which obviously limits the applicability of the outcomes. Pre-exercise (and/or during-exercise) nutrient intake often has a lingering carry-over effect into the post-exercise period. Throughout the day, there's a constant overlap of meal digestion & nutrient absorption. For this reason, the effectiveness of nutrient timing does not require a high degree of precision.
The Primary Laws of Nutrient Timing
The First Law of Nutrient Timing is: hitting your daily macronutrient targets is FAR more important than nutrient timing.
The Second Law of Nutrient Timing is: hitting your daily macronutrient targets is FAR more important than nutrient timing.
