As a new runner running a marathon for the first time, I did some research and learned about this strategy called carb-loading. Unfortunately, I had no idea what to do apart from consuming more carbohydrates in the lead-up to the day. How many carbs did I need? How often should I eat carbs? And what carbs should I eat?
Well, those were important questions I didn’t know the answers to. Having run more and learned more, I found ways to answer those questions, and yet, I’m still not convinced I know everything there is to know about carb-loading. So, this is a guide, but I’m still a beginner. Come along and learn something with me, and let’s smash those PBs together.
What is Carb-Loading?
Runners and athletes use a strategy known as carb-loading to prepare for long-distance races and other endurance events. As its name suggests, it involves increasing carbohydrate intake in the days leading up to the event. The goal is to maximise muscle glycogen stores, providing a readily available energy source that delays fatigue and enhances endurance performance.
What’s the Science Behind Carb-Loading?
The body’s preferred energy source during endurance exercise is carbohydrates. When glucose, obtained from carbohydrates, isn’t used immediately, it’s stored in the muscles and liver as a fuel reserve called glycogen. Depleting our glycogen stores leads to fatigue, often called “hitting the wall,” and hampers our ability to continue.
Strategies such as carb-loading may help delay this by ensuring our muscles remain fully stocked with glycogen before starting a long-distance race. Research suggests that high-carb intake in the 24-48 hours before a race can significantly improve performance.
When Should I Start Carb-Loading
Timing is crucial in carb-loading, just as much as the carbohydrates themselves. The typical approach to carb-loading begins 48 hours before the event. Some runners incorporate a depletion phase before carb-loading, which involves an initial intense exercise combined with a low-carbohydrate diet to deplete glycogen stores, followed by a high-carbohydrate diet to maximise glycogen levels.
However, recent research suggests that the depletion phase may not be necessary, and simply increasing carbohydrate intake in the days leading up to the event can be effective. The key is to taper training while increasing carbs, allowing glycogen stores to fill without burning too many calories and utilising those glycogen stores.
That’s Great, But How Many Carbs Do I Need?
Research suggests consuming more carbohydrates two days before a race can significantly improve your running performance. The amount of carbohydrates required varies depending on body weight, training level, and race length. However, there are some commonly accepted guidelines that I tend to follow.
- 5-7g per kg of body weight for moderate endurance training such as 10k and half marathons.
- 7-10g per kg for longer endurance events like marathons.
- 10-12g per kg for ultra-endurance events. Focusing on easily digestible carbs, such as rice, pasta, potatoes, and fruits, can help optimise glycogen stores while minimising digestive distress.
Common Carb Loading Mistakes
Overeating Fat and Protein—Even as I write and research this, I know I’ll feel guilty about breaking this rule again. However, carb-loading doesn’t mean eating excessive amounts of food. High-fat and high-protein meals can slow digestion and cause bloating. During my last ultra, I had mac and cheese the night before. Maybe that’s why I DNF’ed.
Ignoring Fiber Intake—While fibre is essential in a regular diet, too much before a race can lead to gastrointestinal discomfort. When possible, choose low-fibre, high-carbohydrate recipes when planning your carb-loading menus.
Not Drinking Enough Water—One key aspect of carb-loading was one of the main components I often overlooked. And that’s hydration. Water is essential for the body and crucial to effectively carb-loading. Glycogen binds to water, so staying hydrated is critical to maximising glycogen storage. When I drink more water in the days before my long runs, I feel more energised when I’m out.
Trying New Foods – As a chef, I’m always interested in trying new foods and finding new recipes. Yet, as a runner preparing for a race, I need to remain vigilant about trying new things in the days leading up to a race. The last thing I need on race day is any unwanted surprises. That’s why I have the same breakfast before every race—pancakes with maple syrup.
So How Can I Carb-Load Effectively
Focus on Simple Carbs: While wholegrain carbohydrates may be healthier overall, white rice, pasta, and white bread are easier to digest and quickly replenish glycogen stores. While some of my recipes might call specifically for wholewheat bread or pasta, they can often be easily replaced with refined versions.
Spread Intake Throughout the Day: Eat smaller, carb-rich meals every 3-4 hours instead of large meals. This aids digestion and maximises glycogen storage. It will also help keep you feeling full, as blood sugar levels drop significantly after eating simple carbohydrates, increasing hunger. Larger, spaced-out meals may have the same calories as smaller meals, but blood sugar drops may result in hunger and overeating, leaving you bloated.
Avoid Excessive Fats and Fiber: As mentioned above, fats and fibre slow digestion and can cause bloating.
Drink Fluids: I drink a lot of coffee and have recently stopped drinking soda. I still drink a lot of coffee, but I’ve replaced my fizzy sodas with flavoured sparkling water. The result has left me feeling more energised. This might be because water and electrolyte drinks help glycogen synthesis and prevent dehydration.
Monitor Portion Sizes: It might seem like it, but carb-loading doesn’t mean overeating. Calculate how much carbohydrates you’ll need by using the guidelines set out above based on your body weight.
Some Ways I Like to Carb Load
Breakfast – Porridge with white chocolate and raspberries alongside a medium-sized banana.
Snack – Rice cakes with black coffee. I don’t like rice cakes alone, but they have become one of my favourite snacks when dipped into coffee.
Lunch—I struggle with lunch, especially while working, so I find a quick sandwich the safest way to consume a decent amount of carbohydrates. I often have tuna mayo or grilled chicken.
Dinner – Grilled chicken with pasta and tomato sauce. Sometimes, I like to serve my air-fried chicken Milanese alongside a rocket salad, but I haven’t posted that recipe yet. Sorry.
Pre-race snack: Two American pancakes and golden syrup help give me a quick burst of energy before starting my run.
The Last Supper
This is the last meal before your race, and it will often happen the night before a race since most events start in the morning. Keep it simple, familiar, and carb-focused. A moderate portion of pasta, rice, or potatoes with a lean protein source and minimal fat is best. Hydrate well, but don’t overdo it.
Carb-loading can be incredibly effective when done correctly. When used as an excuse to overeat, it may leave you feeling sluggish, a feeling you don’t want the morning of your race. However, carb-loading can significantly improve endurance performance, helping you stay energised and strong throughout your race. So, eat well and run better.
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