Educational Block – Nutrition in Endurance Races: Sugars and Digestive Comfort
These days, a quick glance at the sports nutrition shelves reveals widespread confusion about what's best to consume. Many athletes question the need for and costs associated with new products, but most are looking for just one thing: to reduce gastrointestinal (GI) discomfort during exercise.
To understand which options are best and how to use them, we need to understand the different types of sugars used and how they affect our bodies during endurance events.
blog › artiCLE #2
Sugars: what they are and what they are for
Sugars are carbohydrates (CHO). They come in simple (glucose, fructose, galactose) and complex (maltodextrin, starch, fiber) forms. During exercise, the body prefers to use glucose as an energy source. During long races, such as ultramarathons or triathlons, CHO requirements increase significantly—up to 90–120g/hour is recommended.
The Challenge: Intestinal Absorption
The problem isn't just ingesting these CHOs, but also absorbing them. The intestines, with reduced blood flow during exercise, become less efficient. This leads to unpleasant symptoms: nausea, cramps, vomiting, or diarrhea.
The solution? "Training the gut" – that is, testing the types and amounts of CHO in training to improve gastrointestinal tolerance and optimize performance.
Types of Solutions Available
🔹 Traditional Gels (Multiple CHO):
Combine glucose (or maltodextrin) with fructose. Each sugar uses a different transporter in the intestine, allowing it to exceed the 60g/hour of glucose alone. Example: GU, Clif, Precision Hydration.
🔹 Hydrogels:
Drinks with pectin and alginate that form a gel in the stomach, accelerating gastric emptying and intestinal absorption. They can reduce GI discomfort with high CHO intakes (>90g/h). Example: Maurten.
🔹 Superfuels (Cluster Dextrin):
Highly branched carbohydrate (HBCD) with high molecular weight and low osmolarity. It empties the stomach more quickly and provides sustained energy. Example: Skratch Super-High Carb.
What Science Says
📌 Recent studies show that hydrogels can reduce GI discomfort and even slightly improve performance (~2%) when compared to standard solutions.
📌 The gut is adaptable: regular practice with these products during training is crucial to avoid surprises on race day.
Summary – How to choose?
✅ Glucose + fructose gels → good absorption + solid performance.
✅ Hydrogels → ideal for high CHO loads, with less GI discomfort.
✅ Cluster Dextrin → stable and efficient option for prolonged energy supply.
🎯 Testing in training, adapting nutrition to your gut's needs, and finding the balance between energy and digestive comfort is the key to a successful race day.
