Carbohydrates and Sports Performance

Tim Stewart from the Sport Dietitians Association explains why carbohydrates are essential for active people and provides tips on how much carbohydrate to eat and when to aid performance and recovery.

Carbohydrates are an essential nutrient. They are required to help you function on a daily basis. More importantly, for the active inpidual, they play a key role in helping you achieve your goals. This article will explore carbohydrates and the role they play during exercise. We will also take a closer look into one of the main sources of carbohydrates…breads, cereals and grains.

But first…What are Carbohydrates?

Carbohydrates are the main energy source for the body, particularly during high intensity exercise, which explains why they are important for active inpiduals and elite athletes. The main storage site for carbohydrates is within the muscles, stored in the form of glycogen. We also have a small backup store of carbohydrates in our liver.

What happens when we run low in carbohydrates? This can lead to an increase in fatigue, reduce your ability to train hard, affect your performance during competition and compromise your immune system. Low carbohydrate levels can also reduce your decision making ability and potentially increase your risk of soft tissue injury.

When it comes to sports performance, not all carbohydrates are the same. An easy way to explain this is through the glycaemic index. As foods with a high glycemic index (GI) are absorbed quickly into our bloodstream. these types of carbohydrates can play a role by being able to provide energy to your working muscles at a faster rate, and are a good way to ‘top-up’ your current glycogen supplies within your muscles.

In foods with a lower GI the energy from the carbohydrates becomes available at a slower rate. These carbohydrates play a more active role in terms of preparation to a competition or as part of a recovery meal.

How much do you need?

For the active inpidual or elite athlete, the amount will depend on how active you are as carbohydrates provide us with the necessary energy to participate in exercise or competition. If you have a lot of activity to do on a particular day then you need to match this with a higher carbohydrate intake. On the other hand, days where your training volume is low require a lower carbohydrate intake.  Each person’s carbohydrate needs are different and it’s important to seek the expertise of an Accredited Sports Dietitian to determine how much you need to provide enough energy to complete your training sessions as well as everyday activity.

Where can we find carbohydrates?

While we are able to get carbohydrates from a wide variety of foods, it’s important to choose carbohydrate options that are packed full of other essential nutrients. This makes breads, grains and cereals a great option. Let’s explore breads, cereals and grains in more detail.

As we know, grains like pasta and rice are jam packed with carbohydrates and are best to be taken as preparation for your sporting event or competition. They do require a bit of digestion so it’s best to have these 3-4 hours prior to your exercise or even the night before.

Breads and cereals can be an important tool in your sports nutrition toolbox because they have lots of varieties. Whole grains are the best way to achieve your daily recommended intake of carbohydrates because they are an excellent source of dietary fibre and contain the plant form of omega-3 fatty acids within the germ of the grain. Whole grains have also been linked to a reduced risk of cardiovascular disease and some cancers (including bowel cancer).


  • Carbohydrates are the main energy source for the muscles and the brain
  • For the active inpidual, your need for carbohydrates increases or decreases depending on the volume and intensity of your activity
  • Breads, cereals and grains are one of the main food sources for carbohydrates and they have added nutritional benefits that may reduce the risk of cardiovascular disease and some cancers including bowel cancer.

How can I include carbohydrates in my training diet?

Depending on your activity, your carbohydrate requirements are going to vary. As a general rule, 25-50g of carbohydrates in the hours leading up to your activity will be enough to ‘top-up’ your carbohydrate stores. Just remember to give yourself enough time for your body to digest your food to avoid an upset stomach.

The table below shows some examples of foods containing 50g of carbohydrates and a guide to when this may be best suited prior to exercise.

*Muesli bars are also a good way to ‘top-up’ your carbohydrate stores between competition if you have 1-2 hours between exercise

As a general rule, leave more time for the body to digest foods that are higher in fibre prior to exercising. This will ensure that all the energy is available to be used and not still being digested when running around. It will also help to avoid unwanted toilet stops!

Tips to remember…

  1. Balance your carbohydrate intake with your exercise requirements.
  2. Aim to eat good quality carbohydrates everyday
  3. Eating too close to when you exercise may result in an upset stomach. Give yourself plenty of time to digest the food
  4. Breads, cereals and grains are excellent sources of carbohydrates to ensure you are fuelled up and ready to go!

To find an Accredited Sports Dietitian visit the Sports Dietitians Association.

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