The Chilly Half marathon is this upcoming weekend, which means I will receive many questions in the days leading up to the race about in-race fueling. Unfortunately, it’s too late for me to help these athletes. Just like you wouldn’t start a race without putting in the proper training, our gut must also be properly prepared for race day.

The gut is an adaptable organ and should be trained just like other muscles in order for us to perform at our best.  This means practicing our in-race nutrition plans.  Consuming carbohydrates during exercise increases our ability to absorb carbohydrates. This is because the practice increases the transporters in our gut which bring the carbohydrates from the gut into the blood stream. Without enough of these transporters, consuming carbohydrates during a race could cause gastro-intestinal issues, such as diarrhea, since they are not properly absorbed.

If you think that you can get away without any in-race fueling during an endurance event, think again. Carbohydrates are the body’s fuel source during exercise. However, the body does not store enough carbohydrates for long-distance endurance events. Without enough carbohydrates, you’ll “hit the wall” or “bonk.” For events over an hour, aim to consume 30-60 grams of carbohydrate per hour of exercise. You should start practicing your in-race fuelling plan once per week at least 5-10 weeks out from your competition in order to allow the gut to adapt its ability to absorb carbohydrates.

Other tips for in-race nutrition plans:

  • Avoid highly concentrated carbohydrates. These can cause water to be drawn into the gut leading to diarrhea and other unwanted GI issues. Avoid highly concentrated carbohydrates such as juice and dilute gels by drinking them with water.
  • Select foods from a variety of carbohydrate sources. Different carbohydrates use different transporters in the gut. Taking in too much of one type of carbohydrate can saturate these transporters. Most gels are designed with this in mind and have the right ratio of carbohydrates to be properly absorbed. For more information on this, read my past blog here.

With all the hard work and time you put into training, don’t neglect your gut. In order to perform at your best, you need to fuel properly while also preventing gastro-intestinal issues that can sabotage your race.

Want a personalized race nutrition place to bring your performance to the next level? I’d love to work with you! Contact me here. If you don’t live in the Brantford area, I also offer skype and phone call consults.

Categories: Megan Kuikman

Megan Kuikman

Hello! I’m Megan Kuikman. I’m a Registered Dietitian with specialized training in sports nutrition. My goal is to help athletes and active individuals achieve a healthy attitude towards health, training, and food. I empower athletes to fuel properly for training in order to restore their health and enhance performance. You can get in touch with me at:


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