How to Carb load for an endurance event

If you just want the calculator and couldn’t care less about the decade of research and trial I’ve put into mastering carb loading - Click here

For everyone else who wants to understand how it works, keep reading because I hand on heart can promise you now that no one has went to the depths I have to master this.

What Is Carb Loading

In short, a carb loading is a short-term, strategic increase in your usual carbohydrate intake designed to MAX out your glycogen (reserve energy stores) before an endurance event.

What the Hell Is Glycogen?

Think of glycogen as a reserve energy pack your body carries around, ready to fuel you whenever you train or move at moderate to high intensity.

Here’s how it works: When you eat carbs (say late at night while Netflix and chill is in full swing), those carbs break down into glucose, which enters your bloodstream for immediate energy. But because you’re not doing much, your body cleverly converts that unused glucose into glycogen for storage.

This glycogen is stored in your muscles (mainly) and liver (minor) - how much you can store depends on your muscle mass and training status (hence the calculator below built on your personal stats).

Next morning, you eat breakfast and go train. Your body first burns the glucose circulating in your blood, then when that runs out it switches to your glycogen stores which re-convert it back into glucose for energy.

After training, your post-workout meal (ideally carb-heavy) it replenishes those glycogen stores, ready for next time. Your glycogen is constantly fluctuating - depleting during exercise, refilling when you eat.

Why Do You Need To Carb Load?

Here’s the problem: When you’re in a calorie deficit, you’re never fully refilling your glycogen stores. Over time, this leads to:

• Tanked energy levels
• Poor training performance
• Skyrocketing hunger
  
  

Imagine this scenario; you're now running a marathon, your body will utilise the glucose from the carb heavy meal you have pre-race, however the event is that long that will barely last you 30/40 minuets. After that you're tapping into your glycogen stores...

Now if you go into an endurance event and you have depleted glycogen stores, it's also going to burn through that super fast! That's runners wall, that is when you crash completely. It isn't your fitness, it's your fuel!

If you're reading this now thinking "OMG this is what happens to me!" Yes you're right.

Let me tell you now, when I implemented this strategy before games of football, and other endurance events, my performance increased tenfold. The difference was night and day. I cannot stress to you the importance of this when it comes to advantage over your opponents.

Now depending on how much lean muscle tissue you have and how well trained you are can dictate how much glycogen you can store in your muscles (hence why I made you a calculator) For example as a 6ft1, 220lb male, I can store up to 1200 grams of glycogen, where say a female 5ft5 135lbs may only be able to store 750g

The key takeaway from this is you understanding you're pre-loading your glycogen stores from a big intake of carbohydrates, and the more full your glycogen stores are the longer you can go.

When Should You Carb Load

Now that you understand what carb loading is, the challenge you face is knowing how depleted your current stores are. This is why I've created 2 calculations. One calculation is for someone not in a diet phase and most likely has 50/70% glycogen stores already.

the other calculation is for someone who is hammering their diet and is most likely sitting at 25/35% glycogen stores.

Your carb load should be done 24 hours in advance to your endurance event, as it can sometimes take a fully day for the carbohydrates to be fully converted into glycogen.

How To Structure A Carb Load

💧 1. Water

Did you know you can hold an extra 1.5–2.5 litres of water when replenishing your glycogen stores, for every gram of glycogen stored, your body pulls in 3-4grams of water. So make sure to drink more than usual throughout the day - otherwise you’ll feel drained and thirsty fast.

🥣 2. Plan Ahead

The last thing you want is a chaotic, unstructured carb load (my speciality) If you’re aiming for 3,000–7,000 kcal (yes, that’s normal), then grams of fat can creep in fast. So pre-plan your meals, log them in the Team RH App, and get your shopping done in advance.

I can’t stress this enough, you will find it extremely difficult not to over shoot fat, it takes practice and planning.

🍭 3. Start with High-GI Foods

Kick off your refeed with fast-digesting, sugary carbs: cereals, white rice, fruit juice, honey, jam, crumpets, etc. These spike blood glucose and insulin, helping replenish glycogen quickly and making you feel human again.

The higher the GI the faster the glycogen conversion. So it would make sense to go high sugar first just to get you back feeling yourself.

After that, move onto complex carbs like non sugary cereal, pasta, potatoes, or rice to sustain glycogen refill through the rest of the day.

🧈 4. Keep Fat Low

High-fat foods slow digestion and interfere with glycogen uptake. Avoid nuts, cheese, fried food, creamy sauces, or high-fat cereals.

Example:

✅ Crumpet with jam = perfect, low fat, low carbs

❌ Jordans Country Crisp = 11g fat per 100g — that adds up fast.