Endurance athletes today have more choices than ever when it comes to fueling for training and racing. But the marketing messages of all those products often leave the impression that any workout regardless of duration or type demands a readily available sports drink, gel, or bar. If you’re training or racing for long periods of time, eating on the fly certainly becomes a necessity. But if you are following a one-size-fits-all approach to how you refuel during both training and racing, you may want to consider a more context-specific approach.
Fuel, Intensity and Duration
During endurance events, your body relies on two basic fuel sources to varying degrees: carbohydrates and fats. Although both are always utilized together (“fat burns in carbohydrate’s flame”), the amount of carbohydrate used relative to fat depends upon the intensity level at which you are moving.
The higher the intensity of the effort, the more carbs burned relative to fat. The lower the intensity, the greater the percentage of fat. This means your need to take in carbs during exercise will depend upon both the intensity of the activity and how long you need to sustain that intensity. In addition, the precise carb to fat ratio depends upon your individual fitness level and physiological profile.
Although aerobic training in and of itself improves your body’s ability to burn a greater percentage of fat, more coaches and athletes are beginning to recognize that how you eat during that training can also influence this equation. This means that if you are constantly replenishing with gels during your training, you may not be training your body to utilize fat as effectively as it could. So this is where a different strategy for training vs. racing can be beneficial.
Fueling During Training Versus Racing
To be sure, refueling during long races is essential. Any race more than a few hours will typically require some refueling. As you should know by now, you shouldn’t try anything new on race day that hasn’t been done in training. So, yes, trying out your nutrition strategy in training before a race is important. But this does not mean that you need to eat that way during all your training, especially early season base training.
There is rarely a need to take in calories during any workout under 90 minutes, especially moderate intensity workouts. This means most of your training under 90 minutes, and certainly under an hour, can be done without supplemental nutrition. It’s after 90 minutes that the need and desire to refuel becomes more pressing. But you can expand that timeframe to two and a half hours or longer. During early base training, I try to extend my long runs up to two and a half hours without any supplemental calories. Of course, you should always drink water and may need some electrolytes in hot conditions.
Abstaining from those gels or bars during long runs and bikes can be difficult at first. But the more experience you have with it, the better your body adapts—mentally and physically. Of course, that’s the idea. You want your body to rely less on supplemental carbohydrates during those efforts. Nevertheless, you will not always feel fabulous during those efforts as your body’s carbohydrate stores deplete. But there is benefit to gaining experience with those low points during training because they inevitably come in races—even in races where you stick to a consistent refueling strategy.
As you get closer to your races and/or as you add intensity to longer workouts, that’s when to start adding supplemental calories during training. Having started with a basic no-fueling strategy, you can gradually add complexity to that strategy by experimenting with different types of foods. Personally, I’m a fan of “real” foods; and by that I mean items with little to no processing, such as dried fruit and nuts or raw fruit/nut bars. As long as the intensity isn’t too great, I like something solid; I reserve gels for higher intensity workouts or races where I need something easier to eat. A good sports drink with slow absorbing carbohydrates also works well. But preferences are highly individual.
Fueling Strategies During Races
For any race under an hour, mid-race refueling isn’t an issue. But the longer your race, the more important a race nutrition plan becomes. During race level intensity, the body can only digest a certain number of calories (roughly 250-350) an hour. Given that you will be burning more than this per hour, the necessity of consistent refueling for any race lasting several hours becomes evident.
The key to refueling during a long race is consistency. This means staying on a pre-determined schedule, whether that’s every 15 minutes, 20 minutes or 30 minutes. Find out what works best for you and stick to it. You might find it helpful to set a timer to remind you when to take a bite of a bar or suck down a gel. Although you will want to drink whenever you eat, you may need to drink more frequently—so work that into your overall nutrition/hydration plan for the race, taking into account the weather conditions you will face.
Another important thing keep in mind when planning your race fueling strategy is whether you will be carrying your own nutrition, using what is available at aid stations, or a combination of both. In a race of only a few hours, I like to tuck a few of my favorite gels into the band of my shorts and grab water at the aid stations. But the longer the race, the less likely you can carry all the calories you will need. So it is important to know what the aid stations will supply and to try out those products beforehand so you will not be trying something new on race day. You don’t want to find out in the middle of an important race that the only fuel available is a strawberry flavored gel with double caffeine if you hate strawberry flavored gels and are sensitive to caffeine. So plan ahead.
On the topic of caffeine, some athletes like a bit of caffeine during a race or maybe a pre-race coffee, others don’t. I’m not a coffee drinker and I find my body is highly sensitive to caffeine. I like a limited amount during races, especially toward the end of longer races; but I’m not a fan of all the double-caffeinated gels out there. And there seem to be a lot of products loaded with extra caffeine on the market, which makes it easy to over-consume without even trying if you’re relying on all those products during a long race. So know what’s in those gels and strategize accordingly.
The Bottom Line
The bottom line is that nutritional needs are highly individual. What works for one person may not work for another. So finding the right strategy for your needs requires a bit of experimentation. And keep in mind that your needs and preferences may change from season to season, just as your strategies will vary between different phases of training and racing. Be open to trying new things (outside of high stakes races) and strive for the simplest plan to meet your unique situation.
References
Aird, T.P. et al. (2018, February 23). Effects of fasted vs fed-state exercise on performance and post-exercise metabolism: A systematic review and meta-analysis. Retrieved from https://pubmed.ncbi.nlm.nih.gov/29315892/
Bartlett, J.D. et al. (2014, June 19). Carbohydrate availability and exercise training adaptation: Too much of a good thing? Retrieved from https://pubmed.ncbi.nlm.nih.gov/24942068/
Hawley, J.A. & Burke, L.M. (2010, October). Carbohydrate availability and training adaptation: Effects on cell metabolism. Retrieved from https://pubmed.ncbi.nlm.nih.gov/20871231/
Wojtaszewski, J.F.P. et al. (2002, December 17). Regulation of 5’AMP-activated protein kinase activity and substrate utilization in exercising human skeletal muscle. Retrieved from https://pubmed.ncbi.nlm.nih.gov/12488245/
