Q: At what point in a race should I start to drink cola? And should I train with it?
A: The benefits of drinking a caffeinated, high-sugar beverage, such as Coke, toward the latter part of an endurance event, are well-documented. Research from many institutions has shown it helps mobilize fats and sugar into the bloodstream, making it available for use by the athlete, which should improve endurance performance.
Many athletes, including yours truly, have experienced the boost a few sips of cola can provide during a long-course race. It’s safe to say most people will tolerate and benefit from waiting until late in the run (around miles 16–18) to start drinking cola. Some people will even benefit from drinking 4–8 ounces toward the end of the bike and then again late on the run.
That said, everyone responds slightly differently to ingesting caffeinated cola during exercise. Some athletes who are particularly caffeine-sensitive, or ingest excessive amounts of caffeine in any form, will experience negative effects like jitteriness, G.I. distress, and excessive, urgent bathroom stops, and for those reasons it’s essential to first see how it affects you in training.
I recommend trying cola in training at least 2–3 times. Start your cola experiment during the last third of your effort for the day, and with 4–6 ounces of cola every 15 minutes thereafter. A couple nutritional notes to keep in mind: First, cola does not contain the sodium that your body needs, so you will still need to include sports drinks and electrolyte tabs/supplements to ensure adequate sodium intake; and second, cola does contain a higher concentration of carbohydrate, which can be beneficial later in a race but has also been shown to delay gastric emptying (and thus delivery of necessary carb energy to working muscles). So whatever your final Ironman nutrition and hydration plan is, you will still need true sports drinks. You can try mixing half cola and half sports drink in a bottle (I’d recommend a punch flavor rather than a lemon-lime flavor for a better taste) and see which you like better. For a better tasting delivery, you could also take a few sips (i.e., four large gulps or about 4 ounces) of one, followed by a few sips of the other. Practice early on in your training, and by the time you reach race day, you should have a good idea of how your body responds to caffeinated cola and what will work best for you.
Lauren Antonucci, R.D., is a board-certified specialist in sports dietetics, three-time Ironman finisher and the founding director of Nutrition Energy in New York City.