What is carb cycling and is it right for me?

If you’re wondering whether carb cycling could be for you, the key focus of this dietary approach is energy, a core issue for sports performance. The approach has evolved from a variety of protocols developed to create optimal nutritional support for elite athletes.

If you’re wondering whether carb cycling is good for weight loss, carb cycling is a short-term plan. Although some athletes (in sports where weighing in is a factor) may use this approach to manipulate weight in the short term, carb cycling is not designed to support healthy, systematic and sustained weight loss.

Carb cycling for sports performance 

One of the main objectives of sports nutrition is to provide athletes with the energy for sports performance. Protocols have been developed for athletes to manipulate their nutrition for improved energy by adjusting macronutrient (carbohydrate, protein, fat) intake. 

Protocols for the week before an important sports event include the classic (Scandinavian) or the modified protocol. A one-day protocol for the day before has also been developed. 

Carbs as fuel 

Carbs are the most energy-efficient fuel for the body. Carbs are stored in the body as glycogen, mainly in muscles and some in the liver, with a small amount of glucose in the blood. Although they are the most efficient fuel for energy, the amount of carbs the body can store is limited.

Sports performance depends on the immediate availability of energy. Eating carbs at the right time ensures they are available for sports performance. An important aspect of sports nutrition is the timing of food. Not only what athletes eat is important but when they eat is vital.

What is carb cycling?

Carb cycling is, quite simply, eating more carbs at some times and fewer carbs at other times, over days or weeks. More precisely, specific amounts of carbs are measured and the timing of meals is carefully planned over a set timeline.

The purpose of a high intake of carbs is to increase fuel for exercise. This is most appropriate in preparation for intense exercise, an event or a competition, supporting better performance and efficient recovery.

The purpose of a low intake of carbs is to train the body to switch from using carbs to using fats for fuel. This is most appropriate during the training season. 

Macronutrients

While carbohydrates are one of the important macronutrients, not all carbohydrates are equal. Some carbs, found in highly processed foods, have few health benefits. Other highly beneficial carbs are found in foods such as whole grains, vegetables, fruits and legumes.

Increasing carbohydrate amounts should not be at the expense of other macronutrients (protein and fat). Athletes depend, not just on carbs for energy, but on a balanced intake of carbohydrates, protein and fat, for performance and recovery. Total calorie intake needs to be appropriate and adequate hydration is essential.

Is carb cycling for you?

If you are an athlete training for an endurance event, such as a marathon or triathlon, carb cycling may be for you. If you are a recreational athlete who enjoys exercise sessions of about an hour a few times a week, you are better supported by a regular diet with balanced macronutrients.

If you choose to cycle carbs for your sports performance, you need to follow a schedule and calculate the appropriate amount of carbs for your body weight. There is a range of recommendations to calculate grams of carbs per kilogram of body weight, depending on the type, duration and intensity of exercise. Once the required amount of carbohydrates is calculated, an app such as Cronometer is helpful to work out the food to provide the amount.

Important factors to consider are the tolerability of the carb intake for your gut and your food preferences. 

Personalised nutrition

If you have set yourself new goals in sports performance and are committed to improving your sports performance, a personalised nutrition plan helps you to give yourself the best chance of success, by:

• understanding your goals
• following your training plan
• identifying what is right for you
• preparing you for your event
• supporting your recovery

References

• Bergström, J., Hermansen, L, Hultman, E. et al (1967) Diet, muscle glycogen and physical performance. Available at: https://pubmed.ncbi.nlm.nih.gov/5584523/ (Accessed 5.8.2024)
• Burke, L., Hawley, J., Wong, H et al (2011) Carbohydrates for training and competition. Available at: https://pubmed.ncbi.nlm.nih.gov/21660838/ (Accessed 6.8.2024)
• Bussau, V, Fairchild, T., Rao, A et al (2002) Carbohydrate loading in human muscle: an improved 1 day protocol. Available at: https://pubmed.ncbi.nlm.nih.gov/12111292/ (Accessed 5.8.2024)
• Costill, D. (1986) Inside Running. Benchmark Press
• Impey, S., Hearris, M., Hammond, K et al (2018) Fuel for the Work Required: A Theoretical Framework for Carbohydrate Periodization and the Glycogen Threshold Hypothesis. Available at: https://pubmed.ncbi.nlm.nih.gov/29453741/ (Accessed 6.6.2024)
• Murray, B. & Rosenbloom, C. (2028) Fundamentals of glycogen metabolism for coaches and athletes. Available at: https://academic.oup.com/nutritionreviews/article/76/4/243/4851715 (Accessed 5.8.2024)