What is carb loading?

Carbohydrates play an important role in your nutrition. When they're broken down in your body, they're converted into glucose, which provides your brain and body with energy.

Of course, a diet high in carbohydrates paired with a lifestyle that's low in physical activity will lead to weight gain. But, if you're physically active, carbs are key to fuelling your progress and recovery.

Much of the energy that isn't immediately used for fuel is stored in your liver and muscles in the form of glycogen, which can then be converted back into glucose when you need it.

If you don't have enough glycogen on hand while you're active, your body will use fat for fuel (which isn't as effective energy-wise, as fat's harder for your body to break down).

Carb loading is the process of building up those glycogen stores in preparation for a physical event, like a marathon, ensuring you have that energy reserve when you need it most. And a properly planned carb loading strategy can make a significant difference.

Let's look at the benefits of carb loading, including how much you should consume and when.

If you don't have an adequate store of glycogen during a long physical activity (like a race), you're not going to perform your best.

In order to maximise your glycogen levels ahead of an event, you ideally want to start carb loading one to 3 days before it. Typically, this will be done alongside an exercise 'taper' (when you reduce the intensity of your training in the leadup to the event).

Carb loading isn't an exact science, and knowing when to consume your carbs, how much to consume and which carbs to prioritise will come down to the individual.

As a general rule, you should prioritise low-fat and low-fibre options (lower fibre foods are easier to digest and gentler on your gut) alongside your usual healthy balanced diet.

According to Sports Dietitians Australia, around 3 days prior to your event you might consider increasing your carb intake to approximately:

• Females: 5 to 8 grams of carbohydrates per kilogram of bodyweight (meaning up to 480g for someone weighing 60kg)
• Males: 7 to 10 grams of carbohydrates per kilogram of bodyweight (meaning up to 750g if you weigh 75kg).¹

For a 70kg person, a pre-event carb loading diet might look something like this:

• 2 cups of low-fibre cereal (with less than 1.5g of fibre per serve)
• 1 1/2 cups of low-fat milk
• 40g of dried fruit
• 1 glass of fruit juice

• 200ml of low-fat yoghurt
• 1 cup of tinned fruit (with syrup)

• A sandwich with 3 slices of white bread, 2 slices of lean meat and salad of your choice
• 60g of dried fruit

• 1 piece of fruit
• 600ml sports drink

• 1 1/2 cups of white rice or pasta
• 100g of chicken (skinless breast fillet)
• 1 cup of tomato-based sauce
• 1 1/2 cups of mixed vegetables (such as grated carrot or zucchini, chopped mushrooms and celery)

• 2 crumpets with 1tbsp of jam
• 1 glass of fruit juice

Remember, everyone's dietary requirements are different. If you're undertaking a physical event and want to boost your performance with strategies like carb loading, it's worth consulting an Accredited Practising Dietitian throughout your journey.