Proteins and Carbohydrates – When to eat them, before or after the workout?
This has to be up there with the questions I get asked more often. Everyone always wants to know, what they should be eating before a training or what they should be eating after a training? It´s an important question because, as we are about to see, it could influence your objective. What I am going to talk about in this blog regards all those that are looking to build up muscle. Aerobic exercise is different from resistance exercise and the intake of protein- carbohydrate is also different. Let´s first explain some certain things.
Glycogen- Glucose is stored in the muscles and liver as glycogen. Glycogen is what gives you the energy when you do resistance training. One study even said that as much as 80% of ATP production during such training is derived from glycolisis (1). And different studies have shown that, after high volume bodybuilding workouts involving multiple exercises and sets for the same muscle (2-3), there is a depletion of glycogen in those muscles. Also, various studies have proven that a low muscle glycogen level impairs anabolic (building) signaling and muscle protein synthesis (3-4). And to top that off, another study has shown that glycogen availability also has been seen to slow muscle protein breakdown (5). So, it is pretty safe to recommend a high intramuscular glycogen content at the beginning of the training.
But what about after the training? Well, according to a recent study (6) it depends. They say that ¨consuming post-exercise carbohydrate does not meaningfully enhance anabolism. Moreover, unless you are performing two-a-day workouts involving the same muscle group(s), glycogen replenishment will not be a limiting factor in those who consume sufficient carbohydrate over the course of a given day¨. In other words, it is recommend to eat carbohydrates 2-3 hours before the training, if you do this then you should not worry about eating carbohydrates right after training, you still have a 3-4 hour window. If you train on a empty stomac (which I don´t recommend), it would be wise to eat something as soon as you are done with your training.
Proteins- The building blocks of our muscles. Whenever we train we ¨damage¨ our muscle, so there is a breakdown in proteins. Studies have shown that muscle protein breakdown is only slightly elevated after the post exercise but rapidly rises after that. On an empty stomac this increase is even bigger. When we are building muscles, we don´t want this, we want the opposite, that is why training on a empty stomac is horrible for muscle building.
Insulin- When we eat, the insulin level rises in our blood. Insulin has been demonstrated to reduce protein breakdown (8). And consuming a combination of carbohydrates and proteins has been shown to elevate insulin levels more than just eating carbohydrates alone. So it would make sense to eat (or drink) carbohydrates-protein after the workout. But, if we had eaten something 2-3 hours before our workout those insulin levels would still be high and there wouldn´t be such a rush to eat something right away after the training. You see, when we eat something, insulin concentrations rise up over time. So, for example, if you ate a 45g dose of whey protein it would take approximately 50 minutes to cause blood amino acid levels to peak (9). If you would add carbohydrates to that, the insulin leves would even stay elevated longer.
So to summarize this in plain English: It is recommend for muscle building to eat carbohydrates and proteins 2-3 hours before the training. If you do this then you don´t have to worry about eating (protein-carbs) right after the training!!! You still have a 3-4 hour window space to eat those proteins and carbohydrates. If for whatever reason you train on a empty stomac (which you shouldn´t for muscle building), then it is recommended to eat those carbohydrates-protein right after the training, waiting would just cause more protein breakdown!!!
Hoped you enjoyed it. Until next time.
- Lampbert CP, Flynn MG. Fatigue during high-intensity intermittent exercise:application to bodybuilding. SPorts Med 2002,32(8):511-22.
- MacDougall JD, Ray S, Sale DG, McCartney N, Lee P, Garner S. Muscle substrate utilization and lactate production. Can J Appl Physiol 1999, 24(3):209-15.
- Robergs RA, Pearson DR, Costill DL, Fink WJ, Pascoe DD, Benedict MA, Lambert CP, Zachweija JJ. Muscle glycogenolysis during differing intensities of weight-resistance exercise. J Appl Physiol 1991, 70(4):1700-6
- Churchley EG, Coffey VG, Pedersen DJ, Shield A, Carey KA, Cameron-Smith D, Hawley JA. Influence of preexercise muscle glycogen content on transcriptional activity of metabolic and myogenic genes in well-trained humans. J Appl Physiol 2007, 102(4):1604-11.
- Dennis PB, Jaeschke A, Saitoh M, Fowler B, Kozma SC, Thomas G. Mammalian TOR: a homeostatic ATP sensor. Science 2001, 294(5544):1102-5.
- Lemon PW, Mullin JP. Effect of initial muscle glycogen levels on protein catabolism during exercise. J Appl Physiol 1980, 48(4):624-9
- Schoenfeld BJ, Aragon AA. Nutrient timing revisited: is there a post-exercise anabolic window? Journal of the international society of sports nutrition 2013,10:5
- Greenhaff PL, Karagounis LG, Peirce N, Simpson EJ, Hazell M, Layfield R, Wackerhage H, Smith K, Atherton P, Selby A, Rennie MJ: Disassociation between the effects of amino acids and insulin on signaling, ubiquitin ligases, and protein turnover in human muscle. Am J Physiol Endocrinol Metab 2008, 295(3):E595-604.
- Power O, Hallihan A, Jakeman P: Human insulinotropic response to oral ingestion of native and hydrolysed whey protein. Amino Acids. 2009, 37(2):333-9.
- Post#1: Importance of Protein: Protein Supplementation? (hetfitness.wordpress.com)
- Tips For Eating Before A Workout (health-host.co.uk)
- Carbohydrates Pt. 1 (patrickeleydc.wordpress.com)