Triathlon Nutrition: A Bike Fueling Strategy From an IRONMAN Coach
Kilometer 15 of the Ironman run. Or kilometer 5 of a sprint triathlon. Suddenly it happens. Your legs go heavy, your vision blurs, your motivation drops to zero. It feels like someone pulled the plug from the wall. Athletes call it “hitting the wall.”
Most athletes tell themselves at the finish: “I should have run more.” But as an IRONMAN Certified Coach, after analyzing your data, I’ll tell you something different: “You should have eaten more on the bike.”
The Bike Is Your Rolling Buffet
You have to understand one physiological principle: the bike is your best chance to take in fuel while your stomach can still handle it.
On the bike: Your torso is relatively still, your heart rate is lower (if you ride sensibly), and blood is available to your stomach.
On the run: You shake your entire digestive system, your heart rate shoots up, and blood shifts to your muscles and to cooling (skin). Digestion slows down.
If you think you’ll make up an energy deficit at a run aid station, you’re mistaken. By then it’s too late. Everything you want to burn on the run, you have to “buy” in the bike saddle. But watch your intensity. If you ride far above your FTP threshold values, your stomach may struggle and you may not digest even the best gel.
Math, Not Gut Feeling
At Atte ACADEMY we don’t go by feelings of hunger. Hunger is a delayed signal of failure. We go by numbers.
The human body has limits.
Many athletes can absorb roughly 60 grams of carbohydrates per hour (glucose).
With gut training and the right mix (glucose + fructose), some athletes can work up to 90 g per hour or more. Tolerance is individual.
Do you know how much 90 g of carbs is? That’s roughly 3 to 4 energy gels every hour. Sounds like a lot? Try riding an Ironman on plain water and see what happens at kilometer 30.
The Most Common Mistakes I See in Amateurs
The “picnic” on the bike: They eat solid food (bars, baguettes) at high intensity. The stomach can’t process it, and the result is cramps and vomiting.
Forgetting sodium: Drinking lots of plain water? That’s a mistake. You can dilute the sodium in your blood (hyponatremia). Without enough salt your muscles can stop working properly, even if you have enough sugar. Follow sodium guidance that suits you, and see a doctor if you’re unsure.
One plan in training, another in the race: In the race you take whatever brand of gel the organizers hand out, and your gut gets a shock.
Gut Training Is as Important as Muscle Training
I tell my athletes: “Your gut is a muscle. You have to train it.” You can’t eat low-carb all year and then force 100 g of sugar per hour into yourself on race day. That ends in disaster in the porta-potty (if you make it in time :D).
As your coach, I won’t just calculate your watts. I’ll also calculate your nutrition strategy:
How many grams of carbohydrates you need for your weight and power.
How much fluid you need to drink (based on a sweat test).
When exactly you should eat so you don’t have a full stomach in the T2 transition.
Don’t Want to Get Knocked Out? Have a Plan.
Nutrition is the fourth discipline of triathlon. You can have the best bike and the best fitness, but without fuel the engine shuts off.
Don’t risk months of training on a bad calorie calculation. At Atte ACADEMY I’ll prepare a plan where you’ll know exactly what to eat at kilometers 10, 30 and 80.
Book full coaching including a nutrition strategy. Arrive at the finish strong, not hungry.