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Originally Posted by OatmealFitness
I have always been under the impression that the idea of adding something with a high GI/GL with your protein in a postworkout shake was to increase insulin levels and in turn the anabolic effect, not in order to replace glycogen levels. Some info on the validity of this would be great.
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Post-exercise insulin spiking has become standard practice in fitness circles because of misinterpretation of research done on fasted subjects. As a result, many people believe that unless you consume a fast-acting liquid mix of [insert the latest hyped quickie carb & protein source], you won't achieve the walloping insulin spike supposedly necessary to optimize recovery & anabolism. But here's what everyone misses: the nutrient-mediated insulin elevation required to max out net anabolism is relatively minor; it's about 2-3 times the normal basal levels of insulin (this was seen even in the midst of ample amino acid availability via continuous infusion).
To reiterate, insulin's positive effect on net protein balance is maximal with modest elevations; even less than what's seen during normal feeding. As a matter of fact, a properly placed pre-exercise meal will keep insulin sufficiently elevated even after your training bout is over. To put things into perspective, a regular solid meal can elevate insulin anywhere from 4-8 times fasting levels depending on size, and keep it elevated for a few hours. As little as 6 g of essential amino acids plus 35 g sucrose taken immediately pre-exercise can keep insulin elevated to roughly 4 times fasting levels an hour after 40-50 minutes of resistance training. What do you think insulin levels would look like with a typical preworkout meal or shake containing at least as much carbs & double the protein?
Another little-known fact is that amino acids can stimulate protein synthesis without any additional insulin output beyond that caused on their own. I'm gonna assume at this point that everyone has some protein pre & postworkout, so this is yet another reason to nix the empty-calorie refined carb & go for a more nutritious carb source whenever possible.