By Robert Schinetsky
Carbohydrates are a heavily contested macronutrient these days. Some view it as the ultimate training fuel while others look down on it as the source of all chronic diseases affecting modern day man. Regardless of where you fall on the spectrum of carbohydrate affection/detestment, you should realize that carbohydrates are a primary energy source for your mind and muscles. The more intensity with which you train the greater the demand (and need) there is for carbohydrates in the diet, as they (carbs) provide your body with glucose — the “fast burning” fuel of elite athletic performance. Much is made about the necessity of timing carbohydrates to optimize performance, recovery and body composition, and in this article we’ll discuss the importance (if any) of timing carbohydrates for performance and what benefits it may have.
Carbohydrate timing is a subcategory of nutrient timing, which can be thought of as the purposeful and directed intake of nutrients to favorably affect “the adaptive response to acute and chronic exercise (i.e., muscle strength and power, body composition, substrate utilization, and physical performance, etc.).” In the case of carb timing, we are focused primarily on optimizing our intake of dietary carbohydrate (how much, when, how often, etc.) to boost athletic performance, accelerate recovery, enhance muscle gain and/or fat loss.
10-15 years ago nutrient timing, the “anabolic window” and sipping BCAAs all day long were all the rage and it was common thinking that if you didn’t slam a whey protein shake within 30 minutes of finishing your workout all that effort in the gym would be wasted. However, our knowledge set regarding nutrient timing has massively expanded since the release of those earlier studies notating the importance of nutrient timing. Truth be told, those early studies had a couple “issues”:
● They were short-term, meaning we have no idea if the nutrient timing strategies actually led to long term gains
● Variables tracked in the study usually assessed glycogen replenishment, muscle protein synthesis, or nitrogen balance, which, while decent metrics to track, isn’t as meaningful to the general population as the effects on muscle gain and fat loss
In recent years though, more long term studies have shown that nutrient timing may not be as critical is was initially thought for the casual lifter. However, that doesn’t mean strategically timing the intake of carbohydrates, fats, and protein is completely meaningless. Whether or not you need to consider making carb timing a priority is dependent on several factors, including:
● Modality of training (resistance-training, cardio, HIIT, field sports, etc)
● Intensity of training (training at lower intensities utilize a lower proportion of carbohydrate and higher proportion of fat for energy as opposed to higher intensity training protocols)
● Duration of training (length of a competition or training session will dictate whether or not you will require additional carbohydrates intra session)
● Frequency of training (If you are training multiple days per week or multiple times within the same day, the need for carbohydrate increases as does the importance of timing their ingestion)
● Personal preference (some people feel better consuming carbohydrates before/during training while others feel slow, lethargic, or tired consuming a bolus of carbohydrates prior to exercise)
● Energy intake (depending on whether you are in a calorie surplus, maintenance, or deficit could impact whether your performance will benefit from the strategic timing of carbohydrate ingestion)
If, after going through this checklist, you deem it necessary to optimize your nutritional strategies then we can start to get further into the weeds of carb timing.
The average male stores between 350-500 grams of glycogen in their body. This number is dependant on your training experience as well as the amount of muscle mass you have. The longer and more intense you train, the quicker glycogen is depleted, which can lead to significant decrements in athletic performance and overall work output. The International Society of Sports Nutrition (ISSN) has recommended a carb intake range for athletes of 5-12 g/kg of bodyweight per day. That means your carb intake should be on the order of ~2.3-5.5 grams per pound of bodyweight per day.What dictates your carbohydrate intake requirements are the duration, frequency, modality, and intensity of your training session. For example, research has noted that strength-training athletes do well on 4-6 grams carbohydrate per kilogram of body weight per day, while endurance athletes (and those training 12+ hours per week) should consume a minimum of 8 grams of carbohydrate per kg of bodyweight per day.[1,4]
This is the million dollar question — how many carbohydrates do you need to eat around your training to support optimal performance and enhance recovery. Not as much as you think. In fact, most casual gym rats likely consume far more than they really require. The typical resistance-training workout burns at most 30-40% of muscle glycogen, and that’s if you’re supersetting exercises and really getting after it each and every set.[5,6] Chances are pretty good that the vast majority of people aren’t going balls to wall crazy in their training sessions, but even if you are, realize you aren’t depleting as much glycogen as you may have been led to believe in years past and would probably be just fine consuming a normal, balanced meal before and after your workout. But let’s say you train with the intensity of Dorian Yates or Ronnie Coleman or that you’re field sports athlete engaging in multiple competitive matches per day.. If this is you, then consuming carbs could could significantly improve your training, recovery, performance and muscle growth as studies have shown that consuming carbohydrates in and around training helps to maintain stable blood sugar levels and higher glycogen stores, which translates to better performance and greater work output during training.
Furthermore, carb intake pre/intra workout also helps attenuate muscle damage induced by intense exercise and promotes better acute and long-term training adaptations (a.k.a. gains). And, consuming carbohydrates pre workout also stimulates the release of insulin, which when combined with protein (such as in your pre workout meal) boosts protein synthesis and resists protein breakdown. If you’re training lasts more than 60 minutes the ISSN recommends consuming 30-60 grams of carbohydrates per hour, preferably in the way of a carbohydrate-electrolyte solution. If your training lasts less than an hour (which is the typical resistance-training bout), then there’s no need to be concerned with intra workout carbohydrates unless you entered your workout in a fasted state.
At the end of the day, for the average trainee ensuring sufficient intake of total calorie and macronutrients is more important than timing ingestion of carbohydrates. Consistently hitting your macronutrient targets and chasing progressive overload in your workouts will have far more impact than when or how you divvy up your daily carbs. In the ISSN’s own words: “Meeting the total daily intake of protein, preferably with evenly spaced protein feedings (approximately every 3 h during the day), should be viewed as a primary area of emphasis for exercising individuals.” In other words, priority #1 is optimizing protein intake and timing for those looking to build muscle and strength. Once you have the “basics” down and are looking to optimize things a bit further, strategically timing your carbohydrates may benefit you in achieving that extra 5-10%. Consuming the majority of your carbs pre and post workout helps ensure stable blood sugar levels, prevents excessive muscle breakdown, and supports higher glycogen stores. The body is also most sensitive to carbohydrates peri workout, which means the efficiency with with they will be used is maximized.
1. Kerksick, C. M., Arent, S., Schoenfeld, B. J., Stout, J. R., Campbell, B., Wilborn, C. D., Antonio, J. (2017). International society of sports nutrition position stand: nutrient timing. Journal of the International Society of Sports Nutrition, 14(1), 33. https://doi.org/10.1186/s12970-017-0189-4
2. Essén, B., & Henriksson, J. (1974). Glycogen content of individual muscle fibres in man. Acta Physiologica Scandinavica, 90(3), 645-647.
3. Friedman, J. E., Neufer, P. D., & Dohm, G. L. (1991). Regulation of glycogen resynthesis following exercise. Dietary considerations. Sports Medicine (Auckland, N.Z.), 11(4), 232–243. https://doi.org/10.2165/00007256-199111040-00003
4. Burke, L. M., Cox, G. R., Culmmings, N. K., & Desbrow, B. (2001). Guidelines for daily carbohydrate intake: do athletes achieve them? Sports Medicine (Auckland, N.Z.), 31(4), 267–299. https://doi.org/10.2165/00007256-200131040-00003
5. Essen-Gustavsson, B. & Tesch, P. A. 1990. Glycogen and triglyceride utilization in relation to muscle metabolic characteristics in men performing heavy-resistance exercise. European Journal of Applied Physiology, 61, 5-10
6. Robergs, R. A., Pearson, D. R., Costil, D. L., Fink, D. D., Pascoe, M. A., Benedict, C. P., Lambert, C. P., and Zachweija, J. J. (1991). Muscle glycogenolysis during differing intensities of weight-resistance exercise. Journal of Applied Physiology, 70, 1700-1706.
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