lunes, 25 de julio de 2016

Carbohydrate & Protein for Endurance exercise

For many years it was thought that carbohydrates were for endurance and protein for building muscle so you would often see the marathon runner eating mountains of pasta with a side dish of rice whilst the body builder would be devouring a whole chicken washed down with a protein shake. Over the years we have seen the benefits of combining (macro) nutrients with many studies showing how combining carbs and protein can be useful to both endurance and resistance enthusiasts alike1. With the rise in high fat low carb diets (LCHF) we now see how periods of limiting carbohydrate and increasing fat intake can be beneficial, although based on the current evidence I would not recommend an LCHF diet long term, well, not for anyone who takes part in any sport that requires short bursts of high intensity effort (see post on LCHF).

The next question after “what” to eat is usually “when” to eat it, for example, it is pretty well established that ingesting carbohydrate during cycling improves performance. Again, the benefits of ingesting protein soon after exercise, particularly weight training are well known. The focus of this post is to look at the possible benefits of combining carbohydrate and protein both during and after endurance based exercise. A post looking at the same question but focussing on resistance based exercise will follow soon. 

CHO + Pro: performance 

The first question is, does adding protein to a carbohydrate beverage improve endurance performance? The short answer is not really, the few studies that did show a performance benefit all used a time to exhaustion protocol1. For those not familiar, TTE is as it sounds, basically the participants run or cycle at a fixed intensity (e.g. 65% VO2Max) until they are exhausted and have to stop. While the results from studies such as these can be interesting, they have limited practical application. Whatever the discipline, the aim of endurance sport is to get from point A to point B in the quickest time, not to set off from point A and keep going until everyone else has dropped out and you’re the last one standing. So if adding protein to your carbohydrate drink means you can cycle at 65% VO2Max for 7 hours instead of 5 but makes no difference to your 40km TT then it’s not of much use. However, while adding protein to carbs didn’t have a beneficial effect on endurance performance, it did not have a negative effect and it did help in two key areas listed below.  

CHO + Pro: Muscle damage and soreness 

Creatine kinase is an enzyme that is involved in the breakdown of phosphocreatine to give energy2. Elevated levels of CK are an indication of, amongst other things, skeletal muscle damage following strenuous exercise3.  Several time to exhaustion studies4,5 (yes I know!!) have shown that post exercise CK was significantly lower when a carbohydrate + protein beverage was consumed during the test (cycling) compared to carbohydrate alone. Luckily there are also studies that have demonstrated the same results when a carb + protein beverage was consumed during and immediately after 60km6 and 1hr time trial7. However, it must be noted that in the second study although the level of post exercise CK was 60% lower in the carb + pro group this did not reach a level of statistical difference. Regardless of the result not reaching statistical significance it is still worth considering. These studies also measured the athlete’s own feelings of muscular pain using the 7-point Likert scale, 0 being no pain and 6 being extreme pain and limited ability to move1. Unsurprisingly, as the studies mentioned above all showed that CK levels were lower when adding protein to carbohydrate, muscle soreness was also significantly lower in these groups. 

Practical Application 

As things stand in the current literature adding protein to your during or post-race carbs won’t improve your performance but it will help your recovery. This is particularly important if you have several races that are quite close together and being fresh for the next race is more important than the training adaptations you would gain after a hard session.

Current guidelines are: 0.25g protein/kg body weight/Hr of exercise

So if I were to go on a 4-hour ride it would equal around 72g protein. I usually consume 15-20g on a ride so that leaves around 50 or so grams to eat once I have finished. The amount of protein and when to eat your recovery meal is a whole different topic but usually aim to eat something with around 20g of protein (chicken breast or 3 egg omelette) as soon as possible and then another meal a couple of hours later. I always advise to get your nutrients from food as opposed to shakes etc but sometimes this isn’t practical so a shake immediately after exercise and a meal an hour or so later would also be suitable. 

If you want to know more about our nutrition for performance and recovery please contact us on 


1. B.I Campbell 2014, Sports Nutrition: Enhancing exercise performance. CRC Press
2. McArdle, Katch & Katch 2007 Exercise Physiology; Energy, Nutrition and Human Performance. Lipincott Williams & Wilkins 
3. Oxford concise medical dictionary 7th edition 2003, Oxford University Press
4. Saunders, M. J., M. D. Kane, and M. K. Todd. 2004. Effects of a carbohydrate–protein beverage on cycling endurance and muscle damage. Medicine & Science in Sports & Exercise 36 (7): 1233–1238
5. Saunders, M. J., N. D. Luden, and J. E. Herrick. 2007. Consumption of an oral carbohydrate–protein gel improves cycling endurance and prevents postexercise muscle damage. Journal of Strength Conditioning Research 21 (3): 678–684.
6. Saunders, M. J., R. W. Moore, A. K. Kies, N. D. Luden, and C. A. Pratt. 2009. Carbohydrate and protein hydrolysate coingestions improvement of late-exercise time-trial performance. International Journal of Sport Nutrition and Exercise Metabolism 19 (2): 136–149
7. Breen, L., K. D. Tipton, and A. E. Jeukendrup. 2010. No effect of carbohydrate–protein on cycling performance and indices of recovery. Medicine & Science in Sports & Exercise 42 (6):1140–1148. 

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