Optimize your glycogen loading (without upsetting your stomach!)

Summer is in full swing, and so are the sporting events! If you’re getting ready to compete in an endurance event—a triathlon, marathon, or other summer challenge—you may have heard of glycogen loading.

In a previous article, I explained how this nutritional strategy helps increase your carbohydrate (glycogen) stores in your muscles and liver to delay the onset of fatigue. It’s a bit like filling up your tank before a long road trip—the more energy you have available, the farther you can go without slowing down.

But… as you might expect, eating more means more potential digestive stress. So here’s an updated version of this strategy, with a specific focus: how to eat more without upsetting your digestive system.

The Quick Guide: Why Do Glycogen Loading?

•    For events lasting more than 1 hour and 30 minutes: our glycogen stores are generally not sufficient to sustain the effort.
•    By carb-loading 2 to 3 days before the event, you maximize your glycogen stores while reducing your training volume.
•    Result: more energy, better concentration, and a lower risk of hitting the infamous “wall.”

The problem: digestive symptoms during overeating. In fact, some people experience:
    •    Bloating
    •    A feeling of heaviness
    •    Nausea
    •    Abdominal discomfort

Why? Because they’ve often been told to “eat more carbs,” but without any nuance. So here’s a summary of the key adjustments to help you process all that information.

5 Strategies for Effective AND Comfortable Overload:

1. Choose liquid or semi-liquid foods
Foods that are easy to digest allow you to consume more carbohydrates without overloading your digestive system.
→ Smoothies, juices, flavored milk (cow’s milk or plant-based), fruit compotes, and drinkable yogurt.

2. Choose simple, refined carbohydrates
Foods that are lower in fiber are digested much more quickly and easily.
→ White rice, white bread, sugary cereals, jam, maple syrup.

3. Temporarily cut back on protein
Protein helps you feel full, so if you eat too much of it, there’s less room for carbs. Eating a diet that’s slightly lower in protein during the carb-loading period won’t hurt your performance.

4. Avoid excessive fiber
Although fiber is beneficial in everyday life, it can interfere with your ability to consume large amounts of carbohydrates quickly, and consuming too much of it during this period could lead to digestive problems. 

5. Spread out your meals
It's better to eat more often, in small portions, than to force yourself to eat large meals.

Bonus: Train Your Digestive System All Season Long!
It’s highly recommended to gradually incorporate more carbohydrates into your workouts throughout the season, even outside of the loading phase. Why? Because your digestive system, just like your muscles, adapts to what you put it through. By getting your body used to digesting carbohydrates during exercise, you greatly reduce the risk of digestive issues—both during the loading phase and in competition. This is called gastrointestinal training, an approach based on consistency and gradual progression, and one that is often wrongly overlooked.

In conclusion: A personalized plan can make all the difference

Although glycogen loading may seem simple on paper, adapting it to your daily routine, your digestive system, and your type of event can be complex. If not managed properly, glycogen loading can do you more harm than good.

That’s where a sports nutritionist can really make a difference:
She’ll help you figure out the right foods, the right amounts, and the right time to eat them… without making you sick right before the starting line!

I look forward to supporting you as you take on your next challenges!

Coleman E. Chapter 2 - Carbohydrate and exercise Sports nutrition: a practical manual for Professionals. 5th ed. ed: Academy of Nutrition and Dietetics; 2012.

Jeukendrup A. A step towards personalized sports nutrition: carbohydrate intake during exercise. Sports Med. 2014;44 Suppl 1:s25-33.

Whitney, E., Rolfes, S. R., Hammond, G., & Piché, L. A. (2015). Chapter 4: The Carbohydrates: sugars, Starches, and Fibres. In Understanding nutrition (pp. 96–133). essay, Nelson education.

Hawley, J. A., Schabort, E. J., Noakes, T. D., & Dennis, S. C. (1997). Carbohydrate-loading and exercise performance. An update. Sports medicine, 24(2), 73-81. doi:10.2165/00007256-199724020-00001