How to Consume Calories During Exercise

It’s a long run day. You’ve got your favorite shoes laced up, your most comfortable kit is on your back, and you’re ready to start burning up the pavement. As you walk out the door, it hits you that you’re going to be on the road long enough that you’ll need to refuel. You’ve already got your Stage bottle and backup Stage cartridges ready to go, but you’re drinking for hydration and eating for calories (energy), so you also need to bring some food with you on the road.

What do you reach for?

Many athletes will start a training program, be it for a half marathon or an Ironman triathlon, without giving this question much thought. In reality, most people think more about their scrumptious post-run or pre-race meals than their training fuel. However, this omission is a critical error that can limit your ability to get the most out of your training, no matter how low or lofty your goals are. Whether you’re trying to dominate your hometown Turkey Trot or eyeing a PR in a triathlon, you should be paying as much attention to how you fuel during exercise as any of the other variables that come into play--like pacing, equipment decisions, and hydration protocols.

So what is the ideal way to fuel up during exercise? We’re glad you asked!

Drink for Hydration, Eat for Nutrition

As previously discussed, you should divide your refueling efforts into two categories: hydration and calories. Anytime you work up a sweat, your body needs three things: fluids and electrolytes to replace much of what is lost in sweat, and carbohydrates to fuel your exercising muscles. While your first priority should be replacing fluids and electrolytes to prevent dehydration, consuming adequate carbs to keep your muscles firing is a close second and should not be ignored. By treating hydration and calories as distinct needs, you can exercise full control over how you consume both, which can seriously impact your overall performance. Furthermore, this effect is magnified by using Stage to hydrate, as the revolutionary technology in the Cirkul platform allows you to precisely dial in electrolytes to meet your individual needs.

When you’re on the road, your emphasis should always be on consuming carbohydrates for calories; while protein won’t necessarily hurt you, it’s also not going to have any positive effect from a physiological standpoint. However, protein should still be the king of your post-workout meals, as it is vitally important to promote the protein synthesis that repairs the damage caused by strenuous activity and helps lock in the long-term gains of your hard work.

What Kind of Carbs?


When it comes to consuming calories during exercise, the best advice you can follow is to focus on the foods that you are comfortable with and enjoy. Generally speaking, your body responds best to consuming between 30 and 60g of carbohydrates during each hour of strenuous exercise, with a focus on simple over complex carbohydrates. Active muscles have a tough time using more than 60g per hour, except during ultra-endurance events, and excessive food intake can lead to a regrettable trinity of gastrointestinal symptoms called the “Three Bs:” bloating, burping, and barfing. So you definitely want to ensure you find your sweet spot in that 30-60g per hour range that will fuel your muscles while preventing GI distress, which can sometimes make it nearly impossible to continue exercising.

The best way to identify what carbohydrate sources work best for you is old-fashioned trial and error. Once you have dialed in your carbohydrate needs for a given workout, you can play around with the foods that meet those needs (based on information in the Nutrition Facts Panel) and are appetizing to you. While your running partner may absolutely love carrying pretzels on a long run, you might be better served with an energy bar or carbohydrate gel. The most important aspect of consuming calories during exercise is not so much the source of those carbohydrates, but that you’re supplying enough of them to power your working muscles.

That being said, it’s best to consume simple carbohydrates during exercise, as these are small sugar molecules that are much easier for the body to digest and absorb, while complex carbohydrates take the body longer to process into fuel. Examples of simple carbohydrates include fruits and vegetables, dairy products, candy, and many snack foods. Most of the energy foods marketed to athletes, including bars, gels, and chews, also contain simple carbohydrates.

At the end of the day, calorie consumption during exercise is primarily about identifying and meeting your individual needs. Much like hydration, what works for you might not work for someone else, so taking the time to experiment with different approaches will help you really nail down what you need to stay hydrated, fueled, and ready to dominate whatever goal you set out to achieve.