Protein Timing: Does it Matter?

Protein Timing for Muscle Growth, Recovery, and Power:Does it Matter?

There have been a lot of conversations about protein supplementation and its effect on muscle growth and its role in muscle development in athletes and recreational athletes. Some argue that it is important to supplement prior to and immediately post exercise. Whereas, others have argued that it is best to just supplement at anytime during the day. So, does it really matter when you supplement with protein? The answer is yes and no. It is obvious that resistance athletes must consume upwards of 30% - 50% more protein than that of an endurance athlete (Hoffman et al., 2009). Also, there is evidence that exercise, particularly resistance training and lengthy endurance training, can produce a catalytic (breakdown) cycle within the muscular structure during and post exercise (Ivy & Furguson., 2010) and that this catalytic cycle can lead to reductions in force, power, and strength of future workouts. For a positive recovery to occur a shift must be made from a catalytic state to an anabolic state, and this is why it is believed that the optimal window for a post-exrecise meal is within 30 - 60 minutes (Ivy & Ferguson, 2010). Also, intense exercise enhances protein synthesis, as well as, protein degradation; for this reason it is important to have amino acid availability to mediate the balance between degradation and synthesis (Ferguson-Stegall et al., 2011). Athletes that supplement or increase their protein intake have been shown to increase muscular recovery, decrease muscle damage, and also a reduction in force decrements (Hoffman et al., 2009). So when is it considered the best time to supplement? Is there an optimal ratio between carbohydrates (CHO) and protein? What protein source seems to be the best? There is a large amount of evidence out there that supports supplementation of protein by the athlete, but the differences in the results within research  can make determining an ideal protein ingestion window challenging. 

Most studies that have researched the subject of protein supplementation explore timing, protein source, simple protein supplementation, and dosage size in relation to athlete or non-athletes. Previous studies have demonstrated that protein supplementation at or above recommended levels did not improve lean mass, strength or power in strength and power athletes, however, it is unknown what the parameters were for those studies and whether the participants were heavily observed throughout the course of the studies (Hoffman et al., 2009,). Also, of note is that in one study involving timing where male athletes ages 19 - 23 years in age reported better lean mass gains from protein supplementation when compare to elderly men whom also participated in the same study. Despite these gains it should be noted that there may have been some hormonal differences that lead to the increased gains in the younger athletes (Hoffman et al., 2009,). It was also noted that an increase in the amino acid leucine, found in milk, may have offset those negative muscle gain results in elderly men (Hulmi, Lockwood & Stout., 2010). When comparing  protein supplementation in a previous study, they found that recreational athletes ages 21 - 24 supplementing with 44g of whey protein and 43 g of glucose (1:1 ratio) immediately prior to and post exercise showed the greatest improvement in lean body mass and cross sectional type II muscle fiber size when compared to a similar group that supplemented in the morning and evening (Hoffman et al., 2009). This previous study contradicted the study by Hoffman et al., that found similar results for both the morning and evening group along with the pre & post exercise group when supplementing with 42 g of a proprietary blend of protein (whey and casein). In short both groups showed adequate increases in strength, 1RM, and power, but timing did not make a difference between the statistics between the two groups. This may be because the athletes daily intake of protein was well above the recommended 1.6 - 2.0g/kg, and that the amount of carbohydrates (CHO) in the supplement mixture could have been too low to enhance protein metabolism facilitation (Hoffman et al., 2009) and this might have caused an overload on one singular metabolic pathway (Hulmi, Lockwood & Stout., 2010).  It should be noted that for resistance training the amount of CHO should be between 1.2g and 1.5 g/kg along with 0.4g to 0.6 g/kg of protein at the time of supplementation (Ivy & Ferguson., 2010), and that protein intake should not exceed 2.0 g/kg/d. This is close to a 3:1 CHO:Protein ratio.

Another study looked at comparing the effects of carrying a 25kg backpack on a tread mill for 2 hours while comparing commercially available carbohydrate and whey protein supplements, and whether they aid in the recovery of neuromuscular function post exercise while consumed during exercise (Blacker et al., 2010). In this study Blacker et al, took ten healthy recreational athletic males and broke them into control (placebo), CHO, and protein groups. The subjects performed a muscle testing protocol involving isokinetic flexion and extension contractions of the trunk, knee, and shoulder at two different hertz intervals (20 Hz and 50 Hz), as well as, maximal voluntary isometric contractions with the subject contracting into knee extension (Blacker et al., 2010). These tests were performed prior to exercise, immediately post exercise, 24, 48, and 72 hours post exercise. The results showed that only the protein and CHO groups had a return to strength at 48 hours post exercise (Blacker et al., 2010). This study does not demonstrate the need for protein supplementation to achieve strength or muscle mass gains, however, it does clearly signal the need for increased nutrients while participating in prolonged exercise. Also, the subjects consumed whey protein based beverages. It might also be of importance to note that in a previous study subjects that showed the best development of type I and type II muscle fibers, and demonstrated a positive muscle protein balance consumed 15g of whey protein prior to and post exercise (Hulmi, Lockwood &; Stout., 2010). Also,  several other previous other studies have shown recreational athletes and previously sedentary individuals to demonstrate an increase in muscle mass when whey protein was consumed and that there were minimal differences between male and female subjects. (Hulmi, Lockwood & Stout., 2010).   

Does this mean that chocolate milk might be a great post exercise drink? According to research the answer would be yes. Whey is definitely a great source of protein for the musculoskeletal system, given that you are not lactose intolerant or have whey allergies. There have been several studies that have looked at the consumption of chocolate milk as a recovery supplement, and many studies have found it to be very promising. This subject all on its own could be a completely different article. For instance, one study that looked into the use of chocolate milk in the protein signalling, protein and CHO synthesis and recovery processes had 10 trained (5 men and 5 women) cyclist and triathletes who were physically stressed and broke the subjects into placebo, CHO, and chocolate milk groups(Ferguson-Stout et al., 2011). The athletes in this study performed both 3 doses of a time trial test, a VO2max test, and 3 doses of 1.5 hours of cycling followed by  interval testing for 10 min to exhaustion. Ferguson-Stout et al.,  found that the trained athletes whom consumed a low-fat chocolate milk beverage (1.9 g CHO, 0.6 g PRO, and 0.3 g fat per kg body weight) had a lower test time trial and had an increase in power output when compared to the CHO group. Also, they determined that their finding matched the findings of various other studies that have looked at the benefits of using a protein/CHO recovery drink post exercise (Ferguson-Stout et al., 2011). It is thought that the higher concentrations of leucine and isoleucine may make fat-free chocolate milk an ideal beverage to be consumed immediately post exercise to enhance muscle protein synthesis (Hoffman et al., 2009), also the CHO found in chocolate milk would aid in muscle glycogen restoration.

Research demonstrates the need to consume protein after exercise, but it is best to include CHO within the recovery meal to improve muscle protein synthesis, protein signaling, muscle glycogen restoration and to increase muscular endurance performance (Ferguson-Stout et al., 2011). There is substantial evidence that protein intake immediately prior to and post exercise can improve muscle protein synthesis rate and increase the accretion of muscle protein in resistance athletes looking to add mass and power when compared to similar athletes who delay their post exercise meal (or snack) for a long period of time (Hoffman et al., 2009). It has also been suggested that a CHO:protein supplement be taken immediately post exercise and then again 2 hours after to augment muscle damage, replace muscle glycogen stores, improve or protect immune function, and increase the rate of muscle protein synthesis when compared to  just providing protein or CHO on their own (Ivy & Ferguson, 2009). This statement even further justifies the need to have a post exercise snack or meal that is close to the ratios of 4:1 or 3:1 in CHO:protein. It would also stand to reason from research that whey protein may be more beneficial to an individual looking to add mass and power to their body. Despite the idea of whey being “better” for increasing the size and power of the musculoskeletal system, any protein is be good protein to add mass and permit adequate muscle protein synthesis. The evidence isn’t just for resistance athletes, even endurance athletes can benefit from a good CHO:protein supplement or meal post exercise. So the next time that you exercise don’t feel bad if you think, “What will I eat after this workout?”, and if you are looking to bulk up then go ahead and add in a CHO:protein pre-exercise meal.

References

Blacker, S. D., Williams, N. C., Fallowfield, J. L., Bilzon, J. LJ., & Willems, M., ET. (2010). Carbohydrate vs protein supplementation for recovery of neuromuscular function following prolonged load carriage. Journal of the International Society of Sports Nutrition, 7:2.

Ferguson-Stout, L., McCleave, E. L., Ding, Z., Doerner III, P. G., Wang, B., Liao, Y-H., Kammer, L., Liu, Y., Hwang, J., & Dessard, B. M. (2011). Postexercise carbohydrate-protein supplementation improves subsequent exercise performance and intracellular signaling for protein synthesis. Journal of Strength and Conditioning Research, 25(5). 1210 - 1224.

Hoffman, J. R., Ratamess, N. A., Tranchina, C. P., Rashti, S. L., Kang, J., & Faigenbau, A. D. (2009). Effects of protein-supplement timing on strength, power, and body-composition changes in resistance-trained men. International Journal of Sports Nutrition and Exercise Metabolism, 19. 172 - 185.

Hulmi, J. J., Lockwood, C. M., & Stout, J. R. (2010). Effect of protein/essential amino acids and resistance training on skeletal muscle hypertrophy: A case for whey protein. Nutrition & Metabolism, 7:51.

Ivy., J. L., & Ferguson, L. F. (2010). Optimizing resistance exercise adaptations through the timing of post-exercise carbohydrate-protein supplementation. Strength and Conditioning Journal, 32(1). 30 - 36.