In the run up to marathon day, while some of us relish the chance to stuff our faces with bread and pasta, others dread chomping through gigantic piles of spaghetti.
However you approach your pre-marathon carb loading, bear in mind that you don’t actually need to consume more calories than you were doing during your training, all you need to do is make sure a higher percentage of your calorie intake comes from carbs.
What’s the science behind it?
When exercising, your muscles use stored glycogen and fat as energy sources. But your body has to work harder to burn fat as energy. Glycogen is a more efficient fuel source but your body normally only stores enough fuel for around 90 minutes of exercise. After this time, the glycogen stored in your muscles is depleted, leading to the famous feeling of 'hitting the wall'.
However, studies have shown that by resting your muscles and increasing your intake of carbohydrates (starches and sugars) you can make your muscles store more glycogen than usual – almost double the amount in fact – thus improving your performance massively.
When and how much should I carb-load?
You need to start loading your muscles with glycogen in the week leading up to the race. This is when you should be tapering, so you may not feel as hungry as usual. Try to take on carb-rich meals and snacks immediately after exercise, as this is when the body most readily stores glycogen in the muscles.
Three to four days before the race, you should increase your carbohydrate intake to roughly 10 to 12 grams of carbohydrate per kilogram of body weight. In other words, carbs should make up about 70 per cent of your daily calories.
Cut back on foods higher in fat to compensate for the extra calories from carbohydrates. Two to three days before the race, increase your carb intake further: now 85-95 per cent of your energy intake should be from carbohydrates.
What other foods should I eat or avoid?
During your last week of training, make sure you are consuming an adequate amount of protein so that your muscles can repair themselves. Meat, eggs, beans and pulses are all good sources of protein. Including some fibre rich foods in your pre-race diet will help you avoid constipation but don’t go crazy, you don’t want the opposite effect either. For more advice check out our lowdown on protein.
Try to avoid fats and oils, cheese, cream, bacon, butter and so on as these are high calorie without the glycogen content. They can also cause discomfort and are harder to digest so it’s best to avoid them before a race. Hold the hot sauce too: spicy food is likely to irritate your bowels meaning that less of the nutrients in your food will be absorbed.
In the final day or so before the race, keep protein and fat intake to a minimum. And don’t worry if you seem to have gained a few pounds: the body stores water along with the extra glycogen. You might benefit from keeping a food diary to keep track of your meals.
Which carbs are best?
Rice, potatoes, pasta, bread, bagels, sweet potato, cereals and fruit are all good options. Try to vary your diet as much possible, including some complex carbs (brown rice, pasta, oats) and some simple ones (white bread, white rice) to make sure you’re getting a wide range of vitamins and minerals, but also to ensure you don’t go crazy just eating the same old pasta or rice dish over and over again.
Here are some delicious carb-heavy recipes to try. If they work for you, go ahead and use them in your pre-marathon carb-loading phase. Work out how much carbohydrate you need to consume and calculate your one person measurement of pasta, rice etc. from this. Enjoy!