Carbohydrate loading has gotten confusing with all the conflicting advice about pasta dinners and glycogen stores flying around. As someone who has experienced both the benefits of proper loading and the disasters of doing it wrong, I learned everything there is to know about filling your fuel tank without filling your toilet. Today, I will share it all with you.
Carbohydrate loading for triathlon is both science and art. Done correctly, it fills glycogen stores without digestive distress. Done incorrectly, it creates bloating, weight gain, and race-day bathroom emergencies that cost far more time than full glycogen ever saved.
This three-day protocol has worked for me across dozens of races from Olympic to Ironman distance.
Understanding Glycogen Storage
Your muscles and liver store carbohydrates as glycogen. A fully loaded athlete carries about 2,000 calories of glycogen – enough for roughly 90-120 minutes of hard effort before significant depletion occurs.
Probably should have led with this section, honestly. Understanding the actual capacity of your glycogen stores explains why we bother with loading in the first place.
Longer races require both full glycogen stores and on-course fueling. The carbohydrate loading phase maximizes starting stores while the race nutrition plan extends endurance beyond what stored glycogen alone provides.
Training depletes glycogen. The taper period before racing allows stores to refill naturally. Carbohydrate loading adds additional capacity by increasing carbohydrate intake while reducing training volume.
Day One: Moderate Increase
Three days before your race, increase carbohydrate intake to about 8 grams per kilogram of body weight. For a 70-kilogram athlete, this means roughly 560 grams of carbohydrates – far more than typical daily intake.
Reduce fiber and fat to make room for additional carbs without increasing total food volume. White rice, white bread, potatoes, pasta, and simple sugars replace vegetables, whole grains, and fatty foods.
I am apparently one of those people who needs to eliminate fiber almost completely during loading, and white rice works for me while whole grains cause bloating every time.
Training should be light – just enough to maintain feel without depleting stores. A 30-minute easy swim or 20-minute shake-out run is plenty. The goal is recovery, not fitness building.
Day Two: Higher Loading
Two days before racing, increase carbohydrates further to 10-12 grams per kilogram. This may feel like excessive eating, but the volume should remain manageable because you are eating easily digested foods.
Spread intake across the day rather than stuffing yourself at dinner. Five to six smaller meals digest more easily than three large ones. Snack between meals to reach carbohydrate targets.
That is what makes day two loading tricky for us normal-sized eaters – the quantity feels absurd but the composition makes it manageable. Hydration matters during loading. Glycogen storage requires water – approximately 3 grams of water per gram of glycogen. Drinking adequately ensures full storage. You may notice weight gain from the additional water, which is normal and beneficial.
Training remains minimal. A brief transition practice or 15-minute easy jog maintains neuromuscular readiness without depleting glycogen stores.
Day Three: Race Eve
The day before racing, maintain high carbohydrate intake but allow time for full digestion before bed. Eat your final larger meal at lunch or early afternoon rather than dinner.
The evening meal should be familiar, moderate in size, and easily digested. This is not the time for restaurant experiments or enormous portions. Your glycogen is already loaded – the race-eve meal just tops off and ensures comfort.
Avoid alcohol, caffeine after early afternoon, and anything that might disrupt sleep. Full glycogen stores matter less than arriving at the start rested and hydrated.
Common Loading Mistakes
Eating too much total food causes digestive distress. The goal is shifting composition toward carbohydrates, not dramatically increasing calories. If you feel stuffed and bloated, you are overdoing it.
Fiber intake during loading creates gas and bloating. Whole wheat pasta, brown rice, and vegetable sides seem healthy but cause problems. Switch to refined carbohydrates during the loading phase only.
Waiting until race eve to load misses the full benefit. Glycogen storage takes time. A single massive pasta dinner cannot compensate for inadequate loading the previous days.
Ignoring hydration undermines loading. Glycogen binds with water. Inadequate fluid intake limits how much glycogen your muscles can store. Drink normally throughout the loading period.
Signs of Successful Loading
Slight weight gain of 1-2 kilograms indicates water storage alongside glycogen – this is good. Feeling full of energy without digestive distress suggests appropriate loading. Muscles may feel slightly heavy or full, which is normal.
Problems include bloating, gas, frequent bathroom trips, or feeling sluggish. These indicate too much fiber, too much total food, or individual intolerance to loading foods. Adjust the protocol for future races based on what you learn.
