Periodised nutrition is one of the many key strategies to support athletes in optimising their training adaptations - small consistent tweaks could mean a big overall win. When nutrition is used as a strategic combination with exercise training, you obtain performance adaptations both short term and long term outcomes [1].

These adaptations are not just limited to muscle and metabolic adaptations, but also extends to other body systems such as the gut. Athletes can improve stomach comfort by manipulating their diet to improve gastric emptying and absorption and reduce any gastrointestinal problems during race day [2].

And just in case you didn’t know, optimum gut function equates to optimum absorption of nutrients. It’s the energy currency your body needs.

Periodised nutrition then is about manipulating your dietary intake to 1) maximise your nutrient intake, 2) support training adaptations and 3) improve long-term performance adaptations sustainably. Let’s face it, you’re in it for the long game, right?

One example of periodised nutrition may include training low. There are a few strategies under this category where athletes train with low glycogen stores. The intended outcome is to initiate certain gene expressions and stress responses so that adaptation can occur.

If you like geeky sports performance research and going deep at a cellular level, then, let’s dive into the science.

Training with low glycogen levels upregulates AMPK, an enzyme that is a potent regulator of muscle metabolism and gene expression. Furthermore, the increase in AMPK expression is associated with mitochondrial biogenesis – the replication of “battery cells” called mitochondria where energy is made in the heart of every cell. And mitochondria is abundant in muscle tissues [3,4]. This research is still in its infancy in the athletic scene and further long-term studies need to be conducted to confirm its results. Nevertheless, knowing that science can open up doors to optimise human performance is one exciting journey.

What does all this mean? Restricting carbohydrate intake with specific training sessions MAY amplify training adaptations based on the upregulation of AMPK, and enhance fat oxidation [5]. The caveat? Over utilising of this strategy without a tailored nutrition plan may hamper recovery, immune function and negatively impact sleep. As always, seek qualified guidance.

Another form of periodised nutrition where nutrient intake is manipulated to increase absorption rates are carbohydrate sources in the form of fluid. Sports gels and drinks aimed at glycogen replenishment and rehydration during an event usually results in stomach discomfort, limiting absorption rate resulting in less carbohydrate uptake and oxidation (burning of carbohydrates for use as fuel).

Our gut has multiple transport systems that carries different carbohydrate sources across this membrane and into the body. Both fructose and glucose uses two different transporters (GLUT 5 and SGLT 1 respectively) resulting in better absorption rate with less gut issues. Additionally, the repeated exposure of glucose also increases sodium dependant glucose transporter (SGLT 1) resulting in improved capacity to absorb carbohydrates [2].

How much improvement in performance does ingesting this multiple carbohydrate sources incur?

An 8% quicker cycling trial time compared to glucose alone [6].

So, if your coach is designing a training program for you based on your FTP, a qualified nutritionist should tailor your nutrition intake based on your training program.

Reference:

1. Jeukendrup, A.E. (2017). Periodized Nutrition for Athletes. Sports Medicine.

2. Jeukendrup, A.E. (2017). Training the Gut for Athletes. Sports Medicine.

3. Jorgensen, S.B., Richter E.A, and Wojtaszewski, J.F.P. (2006). Role of AMPK in Skeletal Muscle Metabolic Regulation and Adaption in Relation to Exercise. The Journal of Physiology.

4. Herzig, S. and Shaw, R. (2018). AMPK: guardian of metabolism and mitochondrial homeostasis. Nature Reviews Molecular Cell Biology.

5. Hulston, C.J., Veneables, M.C., Mann, C.H., Martin, C., Philp, A., Baar, K., and Jeukendrup, A.E. (2010). Training with low muscle glycogen enhances fat metabolism in well-trained cyclists. Medicine and Science in Sports and Exercise.

6. Currell, K. and Jeukendrup A.E. (2008). Superior endurance performance with ingestion of multiple transportable carbohydrates. Medicine and Science in Sports and Exercise.

What is Periodised Nutrition?