[Traps]

If your like me, after you get done working out, you mix up a protein shake, and throw in some dextrose or other highly glycemic carbohydrate, and chug it down never really stopping to think exactly what it is your doing, and why your doing it. Yeah, yeah, we've all heard protein is needed to build muscle, so why the sugar? Well we've also probably heard the sugar is to replenish our glycogen stores. Yeah, both are true and good reasons to drink it in and of itself. However in some research I ran accross theres more to the post workout sugar/insulin spike.

I found an interesting article by Dr. John M Berardi, Ph.D. that explains the importance of insulin in protein synthesis and protein breakdown. Apparently insulin plays a large synergestic role when combined with luecine and a proper balance of amino acids in stimulating protein synthesis and preventing protein breakdown.

The article mentions TONS of great points, like combining protein with carbohydrates will produce a greater insulin response then carbohydrates alone. This is important for all those that take creatine monohydrate. He also mentions the protein carbohydrate ratio to take post workout, 0.8g of carbohydrate and 0.4 g of protein / kg of body weight. He also explains why taking too much protein is bad.....

a very high protein meal can actually cause a release of glucagon. Glucagon is a hormone that antagonizes insulin release. So if you eat some protein with carbs, insulin shoots up. If you eat too much protein with carbs, the insulin release may actually be lower. And if this weren't bad enough, glucagon also has another function that we want to avoid. The darn stuff causes the body to convert amino acids into glucose (a process called gluconeogenesis). So take in too much protein and say goodbye to that special amino acid ratio. Instead those aminos become carbs!

I could go on and on, but I'll finish with one last thing. I find this the most intersting of all. He explains how the addition of leucine can increase post workout protein synthesis. If you've been reading around in these forums, i'm sure you've seen me rant a few times about leucine and perhaps even read the study I posted about it. Well, because its a great study and is a major component of this article I'll post it again. First I'll post a teaser about leucine from the article i've been discussing, afterwards will be a synopsis of the actual leucine study.

The results of this study and others have lead researchers to believe that within the muscle cell, there's one particular regulatory pathway for protein synthesis that's stimulated by insulin, but dependent on leucine (27). If insulin is present and leucine isn't, then protein synthesis can't maximally be stimulated. If leucine is present and insulin isn't, protein synthesis can't be maximally stimulated. But give 'em both and look out!

Leucine Study

The present study was designed to determine postexercise muscle protein synthesis and whole body protein balance following the combined ingestion of carbohydrate with or without protein and/or free leucine. Eight male subjects were randomly assigned to three trials in which they consumed drinks containing either carbohydrate (CHO), carbohydrate and protein (CHO+PRO), or carbohydrate, protein, and free leucine (CHO+PRO+Leu) following 45 min of resistance exercise. A primed, continuous infusion of L-[ring-13C6]phenylalanine was applied, with blood samples and muscle biopsies collected to assess fractional synthetic rate (FSR) in the vastus lateralis muscle as well as whole body protein turnover during 6 h of postexercise recovery. Plasma insulin response was higher in the CHO+PRO+Leu compared with the CHO and CHO+PRO trials (+240 +/- 19% and +77 +/- 11%, respectively, P < 0.05). Whole body protein breakdown rates were lower, and whole body protein synthesis rates were higher, in the CHO+PRO and CHO+PRO+Leu trials compared with the CHO trial (P < 0.05). Addition of leucine in the CHO+PRO+Leu trial resulted in a lower protein oxidation rate compared with the CHO+PRO trial. Protein balance was negative during recovery in the CHO trial but positive in the CHO+PRO and CHO+PRO+Leu trials. In the CHO+PRO+Leu trial, whole body net protein balance was significantly greater compared with values observed in the CHO+PRO and CHO trials (P < 0.05). Mixed muscle FSR, measured over a 6-h period of postexercise recovery, was significantly greater in the CHO+PRO+Leu trial compared with the CHO trial (0.095 +/- 0.006 vs. 0.061 +/- 0.008%/h, respectively, P < 0.05), with intermediate values observed in the CHO+PRO trial (0.0820 +/- 0.0104%/h). We conclude that coingestion of protein and leucine stimulates muscle protein synthesis and optimizes whole body protein balance compared with the intake of carbohydrate only.

PMID: 15562251 [PubMed - indexed for MEDLINE]