Periodized Carbohydrate Availability and Other Nutrition Periodization Practices
Periodization has been used in athletes to program training in periods of micro, meso, and macrocycles. The cycles are a means of organizing an athlete’s training plan to build strength, speed, and/or endurance for their season or specific competition/race. Periodization also helps athletes optimize training by providing scheduled rest and recovery. Nutrition is another aspect that should be considered during the periodization process of an athlete's training plan. Most days will consist of 1-2 training sessions and at least 3 meals. Do you see where I’m headed?... If you are taking time to strategize training, then wouldn’t you want to consider how your nutrition should be adapted to meet your daily training goals to prepare you for your season or specific competition/race.
What is Nutrition Periodization and Periodized Carbohydrate Availability?
Nutrition periodization is “the planned, purposeful, and strategic use of specific nutritional interventions to enhance the adaptations targeted by individual exercise sessions or periodic training plans, or to obtain other effects that will enhance performance in the longer term.” It is the essence of using nutrient, hydration, and supplementation practices to allow the body to adapt to the volume and intensity of training required to help the athlete achieve performance goals. A nutrition practice used among athletes and discussed among sport nutrition and coaching professionals is periodized carbohydrate availability. Periodized carbohydrate availability is the deliberate implementation of low carbohydrate availability, or the “train low” strategy, in 30-50% of training sessions to potentially promote increases in mitochondria mass, enzymatic activity to enhance the use of oxygen by the muscle, and enhancing fatty acid oxidation as fuel.
How is Periodized Carbohydrate Availability Used?
Periodized carbohydrate availability is implemented when the athlete faces altitude/environmental changes, requires changes in body composition, when exercise intensity and duration changes due to changes in training goals. Periodized carbohydrate availability manipulates carbohydrate intakes on a day by day or meal by meal basis. Athletes can vary between “train high” (high to normal carbohydrate availability) and “train low” (insufficient carbohydrate availability) on a day by day or meal by meal basis, depending on the goals of that training session.
“Training high” or with sufficient carbohydrate stores is generally utilized when quality endurance training is key and often for the athlete who are training for and competing in very high intensity or high intensity activities. Essentially the athlete is consuming enough carbohydrates to fuel maximal output and promote beneficial muscle adaptations following performances. The availability of adequate carbohydrates provides the energy to meet high intensity in future training sessions and stimulates the balance of hormones and nervous system changes needed to stimulate appropriate muscle and training adaptations.
“Training low” is used in athletes to promote metabolic adaptations for endurance activities or when higher intensity is not required. The decreased availability of glucose and glycogen stores has shown to result in cellular signaling, gene transcription, and enzymatic processes that enhance mitochondrial mass and improve fat oxidation.
Are there benefits to “training low”?
To that the research answers… it is very scattered and conflicted. Studies vary in their subject use including elite, highly trained, or untrained subjects. Some studies do not ensure calories were similar amidst the manipulation of carbohydrates. There have been various “train low” strategies used to promote low glycogen availability including training twice-day, sleep low, fasted training, etc. There have been various training protocols used to promote glycogen depletion ranging in their duration and intensity. I will continue to explore the literature in subsequent posts which will explore the use of “training low”.
“Fueling for the Work Required”
Instead of “training low”, some endurance athletes use the strategy marked “fueling for the work required” in which a glycogen threshold (100-300 mmol/kg of dry weight) will be reached at some point through the training session to result in “training low” adaptations. The optimal window allows the athlete to reach necessary intensities to induce required adaptations and reduce fatigue and over training. This requires planning and strategizing carbohydrate intakes on a day by day and meal by meal approach depending on the athlete’s training goals. Again, knowing the intention for a training session or macrocycle can guide the nutrition plan! Remember “training low” does not mean habitually low glycogen stores, but rather 30-50% of training sessions are purposefully scheduled to begin without replenishing previously depleted glycogen stores. This concept also support the notion that “training low” would not benefit an athlete in the PEAK/PERFORM period since these efforts are often spent at higher intensities. In future posts I will discuss the details and implications of the “training low” strategy.
The highlight of periodized carbohydrate availability is possibility of allowing the body to be metabolically flexible during steady state, lower intensity training sessions. For endurance athletes, carbohydrates and fats are recognized as key fuel sources, so athletes often manipulate endogenous and exogenous energy sources with training to achieve higher rates of energy (ATP) production for better performances. Specifically manipulating availability of carbohydrates around training sessions has proven to support the adaptations that are gained from endurance training. For strength and power athletes, carbohydrate availability may be adjusted based on training volume, intensity, and body composition goals. However, periodized carbohydrate availability is not studied in strength and power athletes to the extent that it has been studied for endurance purposes. This is possibly due to the known fact that higher intensity performances required from strength and power athletes require adequate carbohydrate availability.
Maximizing the Use of Nutrition Periodization
Periodized nutrition can go beyond carbohydrate availability; you have the capacity to train more than the acute effects of carbohydrate availability on muscle adaptation and primary performance outcomes. Periodized nutrition can be used to improve and promote GI tolerance to specific loads and types of carbohydrates; implement appropriate nutrition and supplementation plans in and out of season that supports strength, speed, and/or endurance training goals; improve microbiome health; understand athlete sensitivity to specific foods; enhance and recover the CNS; acclimatize an athlete to the environment they will compete or race in; support traveling nutrition needs; and/or support short term and long term body composition goals. If nutrition periodization is not considered the athlete may fall risk to overtraining or relative energy deficiency in sport (REDS), suffer from changes in body mass, or reduce their opportunity to get achieve optimal performances supported by their training plans.
The story of nutrition periodization looks different for every athlete since each athlete has various strengths and weaknesses, comes with different sport backgrounds, has different food tolerances, have specific training schedules to match their season/competition/race, and in general have different life and health beliefs/values. For each athlete their lies a unique PREP, PEAK/PERFORM, and POST nutrition strategy to help them achieve their optimal performance goal.