Mastering Carb Loading: Essential Tips and Insights for Optimal Performance

When most athletes hear “carb load,” the image that pops up is a mountain of pasta with a side of garlic bread. While pasta can be part of the plan, effective carb loading is far more strategic than eating a big Italian dinner.

Who needs to carb load?

Aggressive carb loading is designed for endurance events lasting longer than 90 minutes such as marathons, half marathons, and ultra marathons. If you are preparing for a shorter race like a 5k or 10k, your usual balanced diet is typically enough to top up glycogen stores.

Why carb load?

Carbohydrates are stored in your muscles as glycogen, which fuels muscle contraction. Glycogen is the most efficient energy source for sustained endurance work. When stores run low, fatigue hits hard, often referred to as “hitting the wall.”

Maximizing glycogen availability helps you:

• Delay fatigue

• Maintain pace for longer

• Reduce the risk of late‑race slowdown

How much?

Current guidelines recommend 8–12 g per kg of body weight of carbohydrates in the 24 hours before competition (Thomas et al., 2016). The study underpinning these guidelines fed endurance‑trained athletes 10 g/kg/day of carbohydrate and measured glycogen levels after Day 1 and Day 3 (Bussau et al., 2002). The surprising finding was that muscle glycogen was already maximized after one day, and additional loading did not increase it further. This means you do not need three days of uncomfortable eating. One well‑executed day is enough.

What it looks like in practice

Here is an example from a recent carb load I completed. I weigh 70 kg, so I targeted the middle of the recommended range (10 g/kg/day, 700g carbs):

Practical tips to make carb loading easier

1. Sugary drinks are your friend

Liquid carbohydrates are one of the easiest ways to increase intake without feeling overly full. Soft drinks, juice, and sports drinks all help you hit your target with minimal gut load.

2. Rice is often easier than pasta

Pasta is dense and can leave you feeling bloated. White rice is lighter, less filling, and easier to eat in large amounts. I find I can tolerate it far better during a big carb push.

3. This is not a normal day of eating

Carb loading is a specific, intentional strategy used only before long endurance events. It is not meant to be balanced, it is not meant to be “clean,” and it is not meant to be sustainable. It is a one‑day intervention to maximize glycogen stores.

4. Practice it before race day

Just like pacing, gels, and shoes, carb loading needs rehearsal. Figure out what sits well, what feels too heavy, and what helps you hit your numbers comfortably.

References

Bussau, V. A., Fairchild, T. J., Rao, A., Steele, P., & Fournier, P. A. (2002). Carbohydrate loading in human muscle: an improved 1 day protocol. European journal of applied physiology, 87(3), 290–295.

Thomas, D. T., Erdman, K. A., & Burke, L. M. (2016). American College of Sports Medicine Joint Position Statement. Nutrition and Athletic Performance. Medicine and science in sports and exercise, 48(3), 543–568.