One of the perks of being a serious endurance athlete is being able to keep working out without any punishment. All of these workouts burn a lot of calories and can wreak havoc on your all-you-can-eat buffet.
In fact, you may feel hungry all the time, except during hard training or races. In these situations, the “fight or flight” response kicks in, causing your nervous system to go into overdrive, reducing your appetite and allowing you to focus on the task at hand.
The only problem with this little hormonal autofocus is that it can burn a lot of calories. So if it goes on for too long, say more than 90 minutes, you’ll run out of gas.
Here’s how to refuel your body during a race so you don’t run on an empty tank.
How your body burns fuel when you exercise
When you exercise, your body can draw fuel from several places.
Adipose tissue (through lipolysis – breakdown of fat) Muscle mass (through proteolysis – breakdown of proteins) Carbohydrates (through glycolysis – breakdown of glucose, also known as blood sugar, which is also stored as glycogen in muscles and liver cells).
When your exercise level is low or you’re training in a low heart rate zone, your body burns a higher percentage of fat than carbohydrates for fuel. Even really lean athletes have enough fat to last them for a while, so if you’re eating in recovery mode or building your base, nutrition during a workout is less important. (Still hydrating is important!).
In fact, many athletes intentionally train in a fasted state (i.e., glucose deprived) during this type of training to teach their bodies to better utilize fat for energy. However, as your workout intensity increases, so does your body’s reliance on carbohydrates as an energy source.
If you plan on putting in a serious effort or training for more than two hours, it’s better to fuel with carbohydrates to burn off your body’s glycogen stores.
What is glycogen?
Glycogen is essentially a backup source of blood sugar. It is quickly converted to glucose, which can be used for energy. Liver glycogen diffuses throughout the body, including the muscles, but muscle glycogen only affects the specific muscles where it is stored.
Once your glycogen stores are completely depleted, you will need about 90 to 120 minutes of energy. Then you “blunder” or “hit a wall.”
If you’ve ever been in the middle of a training session and suddenly felt like even the simplest task is a grand challenge, that’s ridiculous. Technically, you can still function at that point, but your performance will suffer because you still have fat stores and muscle left to utilize.
How to refuel during long events (60 minutes or more)
1. Consume carbohydrates wisely
Increase your carbohydrate intake a few days before your race. There’s no easy way to know when your glycogen is at 100%, so avoid the risk by eating a carbohydrate-rich meal a few hours before your race.
2. Refuel aggressively
Instead of waiting until the first signs of fatigue, start feeding your baby about 30 minutes later. Why? Because if you wait to refuel until you’re tired, you’ve waited too long. (Our bodies didn’t evolve to optimize fuel production for a 140.1-mile Ironman race or two centuries.)
During extreme effort, the human body can burn between 800 and 1,000 calories per hour. Unfortunately, we can only absorb about 360 calories of carbohydrates per hour. This means that you are faced with diminishing returns right from the starting line. That’s why it’s important to jump on glycogen replenishment.
There are 4 calories in 1 gram of carbohydrates, so 360 calories of carbohydrates equals 90 grams. But getting those 90 grams isn’t as easy as chomping down on a jelly donut. This is because different sugars are absorbed in different ways and at different rates. For example, if you consume only glucose, you only absorb about 60 grams per hour.
3. Combine types of sugar
There are tricks to maximizing carbohydrate absorption. Fructose is absorbed differently than glucose. It has to pass through the liver. This process can occur at the same time as glucose absorption, so if you combine the two, you should be able to absorb more carbohydrates overall (90 grams per hour).
However, while this number is backed by good science, don’t take it too seriously. Just because you can probably absorb 90 grams of carbohydrates per hour doesn’t mean you should. For a “short” event of 1-2 hours, you probably won’t need 90 grams per hour. Therefore, it is better to avoid digestive stress and stick to 30-60 grams per hour.
However, for longer periods, it’s best to keep 60 grams per hour as a baseline and add up to 30 grams per hour depending on what your system can comfortably tolerate.
90 grams of carbohydrate absorption may seem like a lot, but like most aspects of training, you can increase your body’s ability to process carbohydrates. Start with the amount that suits you and gradually increase your intake. Remember to experiment while training, not during the race.
4. Set a reminder
Also, take advantage of all the advanced data technology you’ve probably invested in. Set a timer on your computer, phone, or biomedical implant to remind you to eat and drink at regular intervals.
How to stay hydrated during the event
While the science behind event feeding is surprisingly vague, the science behind event hydration is relatively solid, so clarifying it can help simplify the feeding part.
Fluid intake depends on how much you sweat, but according to the American College of Sports Medicine, sweat production during an event ranges from 8 to 67 ounces per hour. Finding the optimal hydration level can take time, but cyclists typically start with about 24 ounces per hour. This is about the same capacity as a standard water bottle, so it’s easy to figure out.
Should I use a sports drink?
You may be tempted to fill up your bottle with a sugar-laden sports drink to keep you nourished and hydrated at the same time. While this may benefit your unique physiology, the hypertonic (more concentrated than blood) nature of that delicious drink means it may not be absorbed effectively.
It can cause stomach pain and, as is experienced in many cyclocross races, vomiting. It is better to drink hypotonic (less concentrated than blood) drinks with less sugar. Such solutions tend to be absorbed more efficiently and effectively.
Good sports drinks contain carbohydrates as a combination of fructose and glucose. One serving of Beachbody Performance Hydrate contains 10 grams of carbohydrates, so if you drink 4 servings per hour, that’s 40 grams. This means you only get 20 to 50 grams of carbohydrates (or about 80 to 200 calories) from your diet. That time.
You can always try to consume all your carbohydrates in liquid form, which is not uncommon in triathlons, but this poses some problems. First, if you stick to a hypotonic mixture, you’ll need a lot of water.
Second, eating just one item for hours on end while suffering both mentally and physically can easily lead to taste fatigue. In other words, your aversion to nutrition increases, preventing your exhausted, over-exercised brain from actively eating and drinking. By mixing liquids and solids, you’re more likely to avoid flavor fatigue and maintain your appetite.
What type of food should I eat?
As long as it tastes good and consists primarily of carbohydrates, it will probably work. You want to absorb these sugars quickly, so high-glycemic foods (i.e., foods that quickly raise blood sugar levels) are best in this situation.
Popular foods include bananas, melons, other low-fiber fruits, and mini pretzels. (I also really enjoy an 8oz can of Coke, especially 3-4 hours into a hard event. Long live carbs and caffeine!)
However, for events that are consistently grueling or taxing, like triathlons and marathons come to mind, gels and chews are both easily digestible meal options. Again, read the ingredients to see the source of the sugar.
Triathlon swim dilemma
The Ironman folks out there are probably scratching their heads, considering it’s pretty difficult to refuel while swimming. “Difficult” means impossible.
So make sure you’re well-nourished and hydrated before you start your race, and focus on replenishing your energy the moment you hit the ground. Keep a full bottle by your bike or in your transition bag to drink as much as possible when changing.
When it comes to food, it’s up to you how much you can tolerate or tolerate. If you can take a bite or two during the transition without slowing down, great. Otherwise, be sure to feed them during the first few miles of your bike ride. Remember that it’s easier to feed your dog while riding a bike than when you’re running. So don’t fall behind here.
That being said, it’s important to know what your intake limit is here, as suddenly stuffing your intestines can lead to digestive issues. Treat refueling during this transition period like any other part of your training.
A word about protein
While protein is helpful after an event, it plays little role in nutritional support during the event. Your goal is to restore glycogen as quickly as humanly possible, and protein slows absorption.
The exception is multi-stage races. In this case, you want to keep protein turnover (muscle synthesis and breakdown) as balanced as possible, so it’s a good idea to consume protein during such events. Keep carbohydrates at the forefront of your diet and experiment with protein during your workouts to determine how much you can tolerate.
Final words: Do what you love.
All of this advice is a great starting point for event nutrition, and hopefully a way to troubleshoot your current methods, but determining the foods that are right for you is a matter of personal preference and Remember, biology helps a lot. Never experiment during the race. But don’t be afraid to experiment with different foods, different amounts, and different solid-to-liquid ratios during your training.
Also, don’t be afraid to take samples provided at the race registration booth (for later use) or trick your friends when they have something you haven’t tried.
Find the intersection between what works scientifically and what works personally. Once you discover it, you can’t stop.
