Taper Nutrition & Carbo-loading For Your Next Race
By Holley Samuel MEd, RD, LD, CSSD, CPT
Spring race season is among us, and for many runners, this could mean gearing up for a goal half or full marathon. Hopefully, in preparation for race day, you have been practicing your fueling strategy throughout the training cycle. If not, we will discuss some key strategies to implement during these peak weeks of training to get you prepared to race.
Should I eat less because I am running less?
Taper periods before a half or full marathon are traditionally two to three weeks in length. The volume of training decreases, and recovery is prioritized. For many runners, the taper can feel like a welcome break where training load is reduced intentionally to allow for adequate recovery in preparation for race day. For some, the taper may be a strange time where they feel like they aren’t doing enough. They may long for those higher mileage weeks or feel the need to “test” their performance on training runs to prove that they are still capable of running specific paces or intensities. This is not recommended, as the taper signifies that “the hay is in the barn.” While no more fitness can be gained in the weeks leading up to a race, it can be easy to self-sabotage progress due to restlessness and not feeling confident in training.
Runners may also experience weight fluctuations in the taper, making them feel the desire to cut calories, carbs, weigh themselves obsessively, or increase their mileage. This too can be detrimental to performance because the taper is all about recovery. Being in a calorie or carb deficit state, adding unnecessary training volume, or becoming hyper-focused on weight as a marker of fitness does not promote optimal recovery. Instead, runners should implement recovery strategies like adequate sleep, nutrition, stress management, and training deloading to optimize the effects of their taper. Although this can be mentally challenging, it is the key to experiencing peak performance on race day.
Runners should attempt to maintain their recommended caloric intake needs to achieve a stable energy balance, as they usually would when it is optimized during peak weeks of training. During the two to three days before an event that will take at least 2-2.5 hours or more (like a full marathon) is when a runner should focus on increasing the number of calories that come from carbohydrates.
To Carbo-load or not to carbo-load?
During training, about 45-65% of calories typically come from carbohydrates, but during the 2-3 days before a marathon or long race effort, 65-75% of calories should come from carbohydrates to efficiently top off glycogen stores.
Glycogen is stored carbohydrates, and most humans, on average, can store about 2000 calories of glycogen in their liver and muscles. Endurance efforts lasting longer than 2 hours tend to deplete glycogen storage, which is why it is vital to fuel on long runs and long race efforts. This is essential if the ultimate goal is to run a fast half of full marathon time, as the body will burn through glycogen and carbohydrates more quickly at higher intensities. Runners should also note that every 1g glycogen is stored with 3g water. Water retention is common up to 3-5lb when carbon-loading, however, this is not necessarily a bad thing when considering performance. If weighing oneself creates a barrier to adequate fueling measures, runners should consider avoiding the scale in the days leading up to a race.
Runners- whether male, or female in any phase of the menstrual cycle, focus on eating between 10-12g/kg body weight in carbs the 2-3 days before an endurance event lasting longer than 2-2.5 hours in duration. To put this into context:
150 lb person /2.2= 68kg
68kgx 10-12= 680-818g carbohydrate per day in the 2-3 days leading up to goal race
680g carbohydrate is about 11 bagels worth of carbohydrate
For many recreational runners, who tend to undereat carbohydrates at baseline, this may seem like a lot to take in each day. And these general recommendations may not apply to certain medical conditions or circumstances, however, for most runners, carbo-loading properly will ensure they optimize their chances at a PR in their race.
Practicing these fueling strategies during the entire training cycle and working through training the gut to tolerate sports nutrition recommendations on the run is key to ensuring a good experience is had on race day. In order to eat this many carbohydrates and also reduce risk for gut distress during their race, runners should also consider reducing their fiber intake and ensuring they are optimally hydrated in the days leading up to their race. This can mean using white breads and refined grains over whole grains, drinking liquid carbohydrate sources, reducing veggie intake, and eating frequently throughout the day.
What about caffeine and alcohol?
Other considerations for taper nutrition runners may implement is reducing alcohol and monitoring caffeine intake. While in moderation, alcohol may not decrease performance, in excess it may lead to dehydration, gut distress, and sleep disturbances. Some runners feel avoiding alcohol weeks before their race benefits them, while others find having a drink or two in moderation has no impact on their performance. Caffeine can be used as an ergogenic aid in boosting performance, however for some runners it can suppress the appetite, trigger anxiety or gut distress, and in doses greater than 400mg may also cause dehydration.
If a runner tolerates caffeine well and knows using it during or around their race aids in their performance without any of the aforementioned side effects and has used it consistently in practice, they may not need to worry about altering their caffeine intake. Some runners in this category may even find that decreasing their caffeine intake in the days leading up to the race and then having their regular dose on race day may increase their sensitivity to caffeine and improve performance. This should be practiced in training, though, so no unwanted side effects come as a surprise on race day. Runners who are sensitive to caffeine and unwanted side effects should avoid caffeine around their race.
Implementation
As a dietitian who works with runners on their fueling strategies, I recommend writing out your plan for the days leading up to your race and on race day itself. Write down how many carbohydrates you need to consume and come up with a plan on how you are going to make that happen. Identify where the food is going to come from, if travel will make this more challenging, and troubleshoot your logistics from there. Practice this in training around your long runs and make adjustments if necessary. If you are unsure how to implement this specifically to your situation, work with a sports performance dietitian to develop a plan unique to you.
References
Bob Murray, Christine Rosenbloom, Fundamentals of glycogen metabolism for coaches and athletes, Nutrition Reviews, Volume 76, Issue 4, April 2018, Pages 243–259, https://doi.org/10.1093/nutrit/nuy001
Lara, B., Ruiz-Moreno, C., Salinero, J.J. and Del Coso, J., 2019. Time Course of Tolerance to the Performance Benefits of Caffeine. PloS one, 14(1), p.e0210275.
Vitale K, Getzin A. Nutrition and Supplement Update for the Endurance Athlete: Review and Recommendations. Nutrients. 2019;11(6):1289. Published 2019 Jun 7. doi:10.3390/nu11061289
Wohlgemuth, K.J., Arieta, L.R., Brewer, G.J. et al. Sex differences and considerations for female specific nutritional strategies: a narrative review. J Int Soc Sports Nutr 18, 27 (2021). https://doi.org/10.1186/s12970-021-00422-8
Podcast episodes-
https://anchor.fm/fitcookienutrition/episodes/Fall-Race-Season-Series-Taper-Nutrition-e17m236