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Carbohydrate Cycling for Improved Athletic Performance

Matthew Rowe explains the use of carbohydrate cycling versus conventional dieting for improving an athlete's performance.

As all athletes know, there comes a time when reducing body fat becomes a key goal, especially in the off-season and early pre-season. However, cutting out calories to achieve such reductions in body fat comes at a price for the athlete. Most athletes have high energy requirements, so conventional dieting can cause problems. Lowering calories results in reductions in energy levels and subsequent dips in training performance and recovery, indeed not a desirable situation for any athlete.

Many scientific studies have looked at the problem of calorie restriction versus energy output to try to find a way that will enable athletes to maintain or burn fat while still maintaining performance. A solution eventually showed itself from the world of bodybuilding. For decades bodybuilders have been successfully cutting down on calories in a way that still provides sufficient energy for their training needs. The process is called carb cycling.

The Basics of Carb Cycling

The premise of carb cycling is simple. As the name suggests, you fuel your body with carbohydrates on your training days and severely restrict carbohydrate consumption on low-intensity and non-training days. In other words, when your body requires energy, you provide it when it does not deprive it. This cyclical consumption of carbohydrates ensures that carbs are consumed precisely when needed and reduced when the body has less need for them. The resultant effect is fat burning but without the detrimental impact of energy reduction during workouts.

Nowadays it's not only bodybuilders that use carb cycling for the results it brings. Carb cycling has now become popular in a range of sports from athletics to rugby. Athletes will divide their week into three distinct phases consisting of high-carb days, low-carb days, and no-carb days. On the no-carb days (non-training days) athletes will consume only vegetables as their source of carbs, with the majority of their calories coming from protein to assist in muscle repair and muscle recovery.

No-carb days are then replaced with lower carb-days on low-intensity training days. This will consist of both vegetables and one or two portions of starchy carbohydrates such as porridge oats, brown rice, or sweet potato. These starchy carbs are typically eaten directly before and after the workout to replenish muscle glycogen stores. Then finally high-carb days will allow for up to 300 grams of carbohydrates from all sources of both slow and rapid release carbs.

The Science Behind Carb Cycling

Carb Cycling works based on controlling your insulin levels. By restricting carbohydrates, we lower our body's insulin levels. Low levels of insulin in the body promote the fat burning process through the release of fatty acids. On our low carbohydrate days, our body's insulin levels are reduced, promoting fat burning. While on our high carbohydrate days, our insulin levels rise, replenishing our muscle glycogen and giving us the energy, we need to train. This type of cyclical low-carb diet plan has been proven by the University Hospital of Manchester to result in better fat loss and insulin resistance compared to regular dieting.

The Role of Protein in Carb-Cycling

It is essential that athletes, in particular, consume plenty of protein while following this eating plan and that they also engage in resistance training. This helps preserve muscle tissue, ensuring that muscle mass is not lost. It is recommended that athletes consume no less than 1.2 grams of protein per pound of bodyweight daily. By consuming protein with each meal, athletes will also help to stabilise blood sugar levels and reduce hunger. Protein at breakfast is recommended as too is consuming around six smaller meals a day rather than three large meals.


Carb cycling is not about depriving the body of energy. Successful fat loss for athletes is about balancing their energy needs with their training requirements. While athletes should generally stick to carb-cycling in the off-season only, the recommendations in this article can help athletes to find a successful and proven way of training hard and staying lean without experiencing the undesirable losses in performance or recovery associated with conventional dieting.

Page Reference

If you quote information from this page in your work, then the reference for this page is:

  • ROWE, M. (2013) Carb Cycling For Improved Athletic Performance [WWW] Available from: [Accessed

About the Author

Matthew Rowe, BSc, ACSM is an exercise physiologist and advanced personal trainer at MotivatePT. With over ten years' experience in sports-specific training, Matthew works with numerous athletes and professional sports teams helping to improve physical performance through sports-conditioning and nutrition.