Part 1: Understanding The Role Of Pre-Workout Carbohydrates
Part 2: What Are The Best Pre-Workout Proteins?
Part 3: Intra-Workout Nutrition
There are numerous strategies you can utilize with intra-workout nutrition. Your workout will serve as the catalyst for a window of opportunity which can be greatly taken advantage of or entirely missed. First, it’s important to understand what’s happening to the body when undergoing resistance training. The mode of exercise I emphasise is progressive overload, low volume and high frequency training. Eccentric loading and emphasizing time-under-tension will be crucial components that greatly influence your ability to uptake glucose. The physiologic effects elicited by this type of training will widen this window of opportunity, vastly increasing the potential for muscle growth. There is a pathway called the mammalian target of rapamycin complex 1 (mTORC1) that functions as a controller of protein synthesis based off certain stimuli and availability of key nutrients (it also regulates much more, but we’ll leave that discussion for another time). This is one of the major mechanisms that controls how protein is created. And so, the foundation that this nutrition strategy rests on stems from maximization of mTORC1 signaling.
In brief:
• View your workout as a window of opportunity. A lot of physiological changes take place during and after a workout, and based on one’s goal, can be influenced (or halted) greatly through nutrient type and timing.
• The mammalian target of rapamycin complex 1 is something anyone who wishes to build muscle should be familiar with. Don’t let the overly complicated name intimidate you.
• Smarter choices in protein and carbohydrates trumps quantity. It ultimately comes down to how they’re digested.
The Mammalian Target Of Rapamycin Complex 1: Building Muscle
Resistance exercise is our stimulus for the mTORC1 pathway. The mode of exercise itself has quite a bit to do with how much this pathway is stimulated – the most recent studies show that mTORC1 signaling, and thus, muscle protein synthesis, depend largely on the magnitude and duration of load placed on the muscle, length of time that muscle is under tension, and the velocity of contractile forces generated (a slow eccentric followed by an explosive concentric, for example). During exercise however, muscle protein synthesis is inhibited to a certain degree. This is due to the increase in activity of AMP-activated protein kinase (AMPK). AMPK’s effects oppose that of mTORC1. AMPK essentially gauges the energy status of the cell in which it attempts to establish 24 an equilibrium. When the body is under stress or simply does not have the energy stores necessary to complete physical work, AMPK activates, inhibiting anabolic processes that require ATP and stimulating catabolic ones that generate ATP. This situation, while being beneficial for fat oxidation, is not ideal for muscle growth. Resistance training-induced AMPK activity has been shown to increase by 75% and subsequently reduce 4E-BP1 phosphorylation by 36%. For optimal muscle growth to occur, AMPK’s catabolic-inducing effects during the bout of resistance exercise must be minimized. This can be accomplished simply by nutritional means.
Certain amino acids can also independently stimulate muscle protein synthesis by modulating the activity of mTORC1 and something called the mitogen activated protein kinase (MAPK) signaling cascade. By supplementing with certain amino acids combined with resistance exercise further enhancement of mTORC1 activation via intracellular amino acid sensing mechanisms and, consequently, reduction of AMPK can be achieved. In other words, supplementing with certain amino acids around your workout creates a much more favorable environment for your body to build muscle. While there are several amino acids that have this effect (these are known as essential amino acids), one could argue that the most important one is leucine. Leucine is interesting in that it has been shown to independently stimulate muscle protein synthesis. This is probably because leucine is also an insulin secretagogue – it stimulates the beta cells in the pancreas to release insulin. An increase in plasma insulin further enhances mTORC1 signaling; in fact, maximal stimulation of mTORC1 is dependent on circulating insulin levels (Pasiakos, 2012). So, what is known so far? Building muscle has a lot to do with the stimulation of mTORC1 pathway and the inhibition of AMPK. Moreover, the goal should be to maximize the way in which mTORC1 operates. Thus, the right stimuli must be provided: a specific type of training, lots of essential amino acids, and an increase in insulin concentrations. How is this accomplished in the most effective way possible?
A Superior Form Of Protein
In some instances, branched chain amino acids (BCAAs) ingested around the workout can be a viable strategy. There are three BCAAs: leucine, isoleucine, and valine. These have powerful effects on muscle protein synthesis and can even be oxidized (along with 4 other amino acids) during exercise providing additional free energy to fuel muscle contraction. While BCAAs certainly are a potential strategy, given this plans goal, there is a superior approach – protein hydrolysate supplementation. Protein hydrolysates are essentially partially broken-down proteins. They are neither intact, whole proteins nor free amino acids. Instead, they are mainly comprised of di- and tri-peptides. These are links of amino acids, two and three long. Are these superior to regular, intact protein? Protein hydrolysates that are comprised of mostly di- and tri-peptides are absorbed much, much faster than intact proteins. It is now generally accepted that only di- and tri-peptides, which remain AFTER digestion, are still absorbed intact {Manninen, 2009). These means our bodies can rebuild muscle tissue much more effectively. Casein hydrolysate has been shown to increase the amino acid concentration in the blood 25 to even 50% more (Koopman, 2009). Furthermore, protein hydrolysates have been shown to influence plasma insulin concentrations 28% greater than intact whey protein. That is not to say whey protein is not to be used – this section is specific to intra-workout supplementation. It was found that whey and casein protein hydrolysates elicited roughly 50% more gastric secretion than respective intact proteins (such as regular whey), which was accompanied by higher plasma concentrations of glucose-dependent insulinotropic polypeptide (GIP) during the first 20 minutes of the gastric emptying process. GIP facilitates insulin-release from pancreatic beta-cells, which is certainly beneficial for muscle protein synthesis (Trumper, 2002). Simply put, the body is placed in a favorable environment to build muscle when consuming a protein hydrolysate during bouts of resistance exercise – the bloodstream is saturated with the necessary nutrients and a subsequent insulin spike to shuttle them into the cell, raising its energy status consequently mitigating AMPK activity
The Power of Insulin
The rapid absorption and insulinotropic effect of a protein hydrolysate makes it a perfect supplement for intra-workout use. However, the potential for muscle protein synthesis can be furthered. Protein ingestion will eventually hit a saturation point at which its benefits will be maxed out. What else can be used to stimulate activation of mTORC1? Insulin and carbohydrate metabolism is the logical next variable to address. While it is entirely possible to see a powerful anabolic effect through hyperaminoacidemia (amino acids in the blood) in the absence of hyperinsulinemia, this situation is less than optimal. By combining a carbohydrate source along with a protein hydrolysate during your workout, a synergistic effect on the synthesis of new proteins can be taken advantage of. Carbohydrate intake along with protein hydrolysate ingestion (casein hydrolysate is most often used) has been studied thoroughly. It’s been found that protein synthesis rate is substantially higher with the addition of carbohydrate (Beelen, 2008). Insulin can certainly be induced by numerous compounds, but the most important insulin secratogue is glucose – a carbohydrate in its most humble form. While leucine does stimulate insulin, it has been shown that it is necessary for there to be a rise in glucose concentration for this to happen (Kalogeropoulou, 2008). How much glucose is debatable so as previously established, starting with the lowest amount of carbohydrate needed to elicit the hormonal response and then progressing is the most reasonable route. Naturally the body adapts to this initial amount after some time, so the diet will need to see progression in a calculated manner. The “lowest amount” should not be misconstrued – our bodies can intake and utilize much more carbohydrate during times of physical stress due to glucose transporter type 4 (GLUT4).
Glucose Transport 4
Blood glucose levels are very tightly controlled through several physiological parameters, the main one being GLUT4. GLUT4 is found in skeletal and cardiac muscle and in adipose tissue and is mediated by insulin, so when insulin is released glucose is picked up from the bloodstream and taken into the cell where it can be stored as glycogen. This glycogen can be broken down and used as an energy source. Insulin, along with muscular contraction stimulate GLUT4, greatly enhancing its translocation and glucose uptake (Kido, 2016). In fact, it has been shown that meal-induced increases in plasma insulin along with muscle contractions 27 showed that glucose uptake increased threefold during the 4-hour period following ingestion of 92 grams of glucose. Glucose uptake increased even further when exercise intensity was increased. All of this was due to the GLUT4 transporter (Bradley, 2015). Our ability to utilize carbohydrates during times of intense muscle contractions is quite high. The question then becomes, what type of carbohydrate, during the workout, is best?
Highly-Branched Cyclic Dextrin
The combination of protein hydrolysate and a specific type of carbohydrate intra-workout provides the body with everything needed for muscle growth, maintenance, and repair. Ensuring the cellular energy status is adequate to handle intense, anaerobic training is most readily fixed with the ingestion of something that quickly supplies the body with glucose. Highly-branched cylic dextrin (HBCD) meets the criteria put forth. With HBCD, high levels of blood levels of glucose can be maintained. HBCD is an alterated form of maltodextrin – its molecular weight is relatively high, but the distribution of this weight has been changed due to its branching, making the distribution of weight much narrower (picture a cone shape). This is an important point because this shape and molecular weight allows for easy digestion. The high molecular weight means blood will not be shunted from the working muscle to the gut – extremely important when discussing intra-workout nutrition. Regular maltodextrin on the other hand, has a relatively low molecular weight, which requires more water, redistributing blood volume to the gut – definitely a situation to be avoided during a workout. It was found that subjects given a HBCD based drink felt less discomfort than those given a maltodextrin-based drink during exercise (Shiraki, 2015). Now, it is important to discuss HBCD’s osmotic pressure. Because HBCD is highly soluble, stable in water, and has low osmotic pressure, gastric emptying rate is significantly increased. The more concentrated the HBCD drink is, the faster the gastric emptying rate. Finding the right osmotic pressure is important, otherwise you’ll find yourself running the bathroom, a victim of something known as dumping syndrome. HBCD drinks with an osmotic pressure of 59-160 mOsm will keep gastric emptying rate much slower (Takii, 2005). So, what does this mean? For every 50 grams of cyclic dextrin used, ¾ liters of water should be mixed in. Everyone is different, so it may take some time to figure out the perfect amount of water, but when in doubt, high-ball it. The research conducted on HBCD in correlation with athletic performance has demonstrated substantial benefits. Shiraki et al. found that the time to fatigue was 70% longer in athletes consuming HBCD than that of those consuming glucose or water, performing at 90% of their VO2 max (Shiraki, 2015).
My favorite brand of cyclic dextrin? Definitely Glycofuse by Gaspari Nutrition.
Intra-Workout Nutrition Guidelines
While no one’s plan is the same, the scientific and critical intuition that forms the foundation on which this plan is based, is soundly in place. Women tend to have lower macronutrient needs than men, but there are exceptions – especially those who are highly athletically trained. An example of an intra-workout shake for a 200-220 pound male with training experience could initially look like:
• 50 grams of highly branched cyclic dextrin
• 25 grams of casein hydrolysate
• 5 grams of creatine monohydrate
• All mixed in 1 liter of water
As this male’s strength increases and an adaptation is witnessed, it may change it to:
• 75 grams of highly branched cyclic dextrin
• 25 grams casein hydrolysate
• 5 grams of creatine monohydrate
• All mixed in 1¼ liters of water It is very rare that someone will require more than 50 grams of casein hydrolysate. HBCD can be increase quite a bit however. If the example person above is maintaining the same bodyfat composition (or even getting leaner) and getting stronger, HBCD should be increased (it’s rare for a person to need more than 120 grams of HBCD). These dietary changes should come after changes to the workout plan have been made – that is, gaps in the workout should first be identified and fixed. Once these flaws have been resolved, intra- and post-workout dietary changes should yield noticeable, measurable effects. When one is getting stronger, they most certainly are growing.
So, what are our take-aways from this (rather long) blog post?
• Protein hydrolysates are a superior protein source to consume during the workout. Coupled with an easily absorbed carbohydrate source, an even greater effect on muscle protein synthesis can be seen.
• For this plan, highly-branched cyclic dextrin will be utilized as its properties are exactly what’s needed during the training session
References
Beelen, M., Tieland, M., Gijsen, A. P., Vandereyt, H., Kies, A. K., Kuipers, H., . . . Loon, L. J. (2008). Coingestion of Carbohydrate and Protein Hydrolysate Stimulates Muscle Protein Synthesis during Exercise in Young Men, with No Further Increase during Subsequent Overnight Recovery. The Journal of Nutrition,138(11), 2198-2204. doi:10.3945/jn.108.092924
Bradley, H., Shaw, C. S., Bendtsen, C., Worthington, P. L., Wilson, O. J., Strauss, J. A., . . . Wagenmakers, A. J. (2015). Visualization and quantitation of GLUT4 translocation in human skeletal muscle following glucose ingestion and exercise. Physiological Reports,3(5). doi:10.14814/phy2.12375
Kalogeropoulou, D., Lafave, L., Schweim, K., Gannon, M. C., & Nuttall, F. Q. (2008). Leucine, when ingested with glucose, synergistically stimulates insulin secretion and lowers blood glucose. Metabolism,57(12), 1747-1752. doi:10.1016/j.metabol.2008.09.001
Kido, K., Ato, S., Yokokawa, T., Makanae, Y., Sato, K., & Fujita, S. (2016). Acute resistance exercise-induced IGF1 expression and subsequent GLUT4 translocation. Physiological Reports,4(16). doi:10.14814/phy2.12907
Koopman, R., Crombach, N., Gijsen, A. P., Walrand, S., Fauquant, J., Kies, A. K., . . . Loon, L. J. (2009). Ingestion of a protein hydrolysate is accompanied by an accelerated in vivo digestion and absorption rate when compared with its intact protein. The American Journal of Clinical Nutrition,90(1), 106-115. doi:10.3945/ajcn.2009.27474
Manninen, A. H. (2009). Protein hydrolysates in sports nutrition. Nutrition & Metabolism,6(1), 38. doi:10.1186/1743-7075-6-38
Pasiakos, S. M. (2012). Exercise and Amino Acid Anabolic Cell Signaling and the Regulation of Skeletal Muscle Mass. Nutrients,4(7), 740-758. doi:10.3390/nu4070740
Shiraki, T., Kometani, T., Yoshitani, K., Takata, H., & Nomura, T. (2015). Evaluation of Exercise Performance with the Intake of Highly Branched Cyclic Dextrin in Athletes. Food Science and Technology Research,21(3), 499-502. doi:10.3136/fstr.21.499
Takii, H., (Nagao), Y. T., Kometani, T., Nishimura, T., Nakae, T., Kuriki, T., & Fushiki, T. (2005). Fluids Containing a Highly Branched Cyclic Dextrin Influence the Gastric Emptying Rate. International Journal of Sports Medicine,26(4), 314-319. doi:10.1055/s-2004-820999
Trumper, A., Trumper, K., & Horsch, D. (2002). Mechanisms of mitogenic and anti-apoptotic signaling by glucose-dependent insulinotropic polypeptide in beta(INS-1)-cells. Journal of Endocrinology,174(2), 233-246. doi:10.1677/joe.0.1740233
Thoughts?