A periodized approach to carbohydrate intake means consuming different carbohydrate ratios depending on where you’re at in your training cycle.

Once your 2019 racing goals are set, it’s time to start thinking about how you should fuel for your best performance—namely with carbohydrate intake. What many athletes don’t understand is that your fueling strategies for training and racing should differ. Fueling for training should support optimal training adaptations where race-day fueling should support maximal performance. And that can mean drastically different carbohydrate ratios depending on where you’re at in your training cycle.

The “Train Low” Approach

When carbohydrate is restricted, enhanced training adaptations are commonly reported, which has been given the term “train low.” Training low appears to enhance fat metabolism and may improve exercise capacity. If race-day fueling is optimal, these enhanced training adaptations can improve race-day performance.

Despite the potential benefits of training low, there are negative implications of persistently training this way:

A recommended approach to overcome these negatives is a periodized approach to carbohydrate intake.

The “Train Smart” Approach

“Train smart” recommends that an athlete fuels for the work required. Carbohydrate can be restricted for selected training sessions aiming to enhance training adaptations. When the goal is to perform the highest workload possible, a restricted carbohydrate approach isn’t appropriate. In sessions lasting 60-90 minutes or less, performed at a low or moderate intensity, training low is likely to be beneficial.

Multiple train-smart strategies that appear to enhance training adaptations are reported in scientific literature:

Race Day Strategies

When maximal performance of high-intensity exercise is desired, high carbohydrate intake is key, because carbohydrate is the primary energy source for high-intensity exercise. Contrary to popular belief, one day of carbohydrate loading is just as effective as three days, therefore the day before race day; 8 to 10 grams per kilogram of body mass of primarily high GI carbohydrate such as white bread or energy gels work well.


To maximize performance and carbohydrate loading, training should be tapered leading up to race day. Tapering should begin two weeks prior to race day with a steady reduction in training volume. The final training session should take place in the afternoon or evening two days prior to race day and carbohydrate loading can begin with this post-training meal.

On race day:

Carbohydrate consumed during a race provides an alternative source of energy to muscle glycogen and is used as fast energy. Carbohydrate should also be consumed following high intensity and/or during long-duration exercise to replace used muscle glycogen and to enhance recovery.

Periodized Carbohydrate Intake Reccomendations

Train-low sessions:

Carbohydrate-loaded performance sessions:

This article originally appeared on Trainingpeaks.com.

Ted Munson is the Performance Nutritionist. He comes from a sports science background having worked in elite sport for the past six years. Ted continues to provide sports science support for teams, alongside his MSc in nutrition and physiology, focusing on hydration markers in elite athletes.