Fueling Your Performance: The TCC Carb Calculator

The Science of Absorption

Carbohydrate intake is limited by how fast your gut can transport fuel into the bloodstream.

• Single Source (Glucose): Capped at roughly 60g/hour.

• Dual Source (Glucose + Fructose): By using two different "gateways" in the gut (SGLT1 and GLUT5 transporters), athletes can absorb up to 90g–100g/hour.

TCC Tip: Don't try 90g/hour for the first time on race day. The gut is a trainable organ; practice your fueling in your long Sunday rides and swims to ensure zero GI distress when it matters most.

The "Golden Rule" of 90g/hour

If the calculator recommends 90g per hour, ensure your fuel has a 2:1 glucose-to-fructose ratio.

Since Glucose and Fructose use different "doors" (transporters) to get from your gut into your blood, using both allows you to bypass the 60g/hour limit of glucose alone. Without this ratio, that extra fuel will sit in your stomach, leading to the dreaded "slosh" and GI distress.

Putting it into Practice

1. Calculate: Use the tool above to find your hourly target.

2. Audit: Look at the back of your favourite gels/drinks. Do they hit the target? Do they have a Fructose mix?

3. Train the Gut: Start with 50% of your target during your long Sunday sessions. Every two weeks, increase by 10g until you reach your race-day goal without stomach issues.