Lower Protein to Carb Ratio Impairs Akt/TOR Signaling Pathway after Fasting in Rainbow Trout

"Boy, you need your carbs post workout!" This cornerstone of conventional bodybuilding wisdom is crumbling and a new study, if it had been done in humans, not in rainbow trout, would potentially refute this myth once and for all - at least, if one follows the popular (but false) assumption that it is because you are in a carb depleted or overall fasted state after a strenuous workouts.

A group of European scientists (Seiliez. 2011) investigated the effect of diets with different protein to carbohydrate ratios on the Akt/TOR Signaling Pathway after fasting for 48h. What they found contradicts conventional wisdom:

Activation of the Akt/TOR signaling pathway by refeeding was severely impaired by decreasing the proteins/carbohydrates ratio. Similarly, post-prandial regulation of several genes related to glucose (Glut4, glucose-6-phosphatase isoform 1), lipid (fatty acid synthase, ATP-citrate lyase, sterol responsive element binding protein, carnitine palmitoyltransferase 1 and 3-hydroxyacyl-CoA dehydrogenase) and amino acid metabolism (serine dehydratase and branched chain α-keto acid dehydrogenase E2 subunit) only occurred when fish were fed the high protein diet. On the other hand, diet composition had a low impact on the expression of genes related to muscle protein degradation.

So, not only did an increase in carbohydrates negatively impact muscle protein synthesis stimulated by the Akt/TOR signaling pathway, interestingly it also failed to reduce muscle protein degradation, which is the second reason people use in favor of a high carb meal after workouts (/fasting). 

For people following the research and writings of low carb proponents such as Mauro di Pasquale these results may not be surprising. However, before flushing your weight gainer down the toilette, you should really reevaluate your personal and training goals. For an athlete whose exercise bouts are long and frequent, carbohydrate repletion may well turn out to be beneficial. If not for muscle growth, then for performance maintenance. A general demonization of carbs would thus be similarly inappropriate as the "fat scare" of the late 20th century. It all depends on who you are and what your athletic and aesthetic goals are.

Protein Supplementation in Heavy Resistance Training: "A case for whey protein"

"Protein builds muscle!" < this is a sentence you will read pretty often in the advertisements - sorry, I meant "scientific explanations" supplement producers print onto their product labels to make you buy their newest "invention". In the end, however, it mostly comes down to a blend of different forms of whey protein with added vitamins minerals and digestive enzymes. But do you really need all that? Do you even need whey?

Table 1: Approximate Essential Amino Acid Profile of Various Protein Sources

A group of scientists from Finland (Hulmi. 2010) would probably say "YES!". In a very recent review they come to conclusions which sound pretty similar to what you can read all over the web:

Most, but not all studies have shown that supplementation of whey alone or with carbohydrates immediately after and possibly before and during resistance exercise can enhance the muscle hypertrophy response to resistance training in healthy adults. Such a response seems to at least be the case when comparing the effects of whey versus a non-energetic, or carbohydrate or soy protein alternative. Some studies also suggest that whey may enhance recovery from heavy exercise and possibly decrease muscle damage and soreness. This could, over time, enhance training adaptations by way of increasing training volume or reducing the potential for over-reaching/over-training.

There is another point, where Hulmi et al. reasoning is pretty much in line with main-stream "bro-science" and this is the extraordinary role of leucine in terms of muscle protein synthesis and hypertrophy:

[Leucine] is probable that the most important component in whey, for increasing protein synthesis and skeletal muscle size, is its high concentration of the BCAA, leucine (see
Table 1). Leucine, acting as a signaling molecule in the mTOR cascade, has been shown to be a critical amino acid for increasing skeletal muscle protein synthesis, both in vitro and in vivo in humans and rats. Leucine may also be involved in suppressing muscle protein degradation.

Their perspective is yet a little more differentiated:

However, if recent data involving rodents can be duplicated in humans, leucine concentrations from whey may only affect peak activation of skeletal MPS but not the duration of MPS or duration of mTOR signaling. Similarly, despite the positive effects of leucine per se, it likely is not the sole factor responsible for whey-induced adaptations to resistance training. For example, adding leucine to intact protein has been shown to offer little, if any, effect on protein synthesis and protein balance when consumed after resistance exercise.

Bottom line: If you go for muscle, go for whey and get drag yourself to the gym ;-)