In interview, AI speaks with sports scientist Alexander Macey to unpack one of the most misunderstood pillars of performance: nutritional periodisation. We discuss carbohydrates, macronutrient timing, mesocycles, recovery physiology, and why semi-professional athletes often fail at the final hurdle.

AI: To begin, what is nutritional periodisation, in practical terms?

Alex:

“Nutritional periodisation is essentially the practice of adjusting what you eat to align with what you’re doing in training. It’s about making nutrition fit the purpose of the training block.

If you take a boxer preparing for a fight, early in camp their energy turnover might be enormous. They may require something like 4,000 calories per day because the training load demands it. As they get closer to weigh-in, they’ll shift into a deficit — perhaps down to 3,750 calories — but the foods they choose must still support the training. Even in a deficit, the diet remains carbohydrate-focused because boxing relies heavily on glycolytic energy systems.”

This reflects the broader scientific definition: matching energy and macronutrient intake to training phases to optimise adaptation and performance (Burke et al., 2011).

AI: How do you approach balancing carbohydrates, protein, and fats across a training cycle?

Alex:

“For recovery across the day, carbohydrates and protein are key. Carbs enable glycogen replenishment; protein provides the building blocks to repair muscle tissue. But fats play an overlooked role too — especially unsaturated fats, which support hormone function and immune health.

Athletes sometimes fear fats, but very low-fat diets can compromise immunity and recovery. So, alongside carbs and protein, we maintain a consistent intake of mono- and polyunsaturated fats.”

This aligns with established sports nutrition guidelines, which highlight that adequate fat intake is essential for immune and hormonal function and should not be unnecessarily restricted (Thomas et al., 2016).

AI: What about nutrient timing across the day? How important is it for athletes who train multiple times?

Alex:

“It’s extremely important to time your nutrition around the hardest session of the day. Most athletes have one key session, even if they train twice.

You need carbohydrate availability going into that session. You don’t want carbs sitting undigested in your stomach, but equally you don’t want to go in under-fuelled. Generally, a carbohydrate-rich meal around 1–4 hours before exercise works well, with many athletes preferring the 3–4 hour mark for larger meals.”

This directly reflects the carbohydrate timing guidelines of 1–4 g/kg of carbohydrate taken 1–4 hours before exercise (Burke et al., 2011).

AI: Many athletes rush for a protein shake immediately after training. Is that actually necessary?

Alex:

“It’s almost instinctive — they finish the session, and race for a shake. But the research is clear: total daily protein intake matters more than immediate timing. Alan Aragon and Brad Schoenfeld demonstrated that the so-called ‘anabolic window’ is far more flexible than people think (Aragon & Schoenfeld, 2013).

What is time-sensitive is carbohydrate. After intense training, glycogen is depleted and the body is primed to restore it. Glycogen resynthesis rates are highest in the first few hours post-exercise and gradually decline over the rest of the day. If an athlete hasn’t used intra-session carbohydrates, the priority is fast-acting carbs straight after the session to start replenishing intramuscular glycogen.”

This is fully in line with the “fuel for the work required” model and carbohydrate recovery research showing glycogen restoration is fastest early in the recovery window (Impey et al., 2018).

AI: Let’s talk training structure. How does nutrition need to adapt as athletes move through mesocycles?

Alex:

“Training does not progress linearly. It progresses through mesocycles — strength, hypertrophy, power, endurance — each with different energy and recovery demands. As volume increases across say for example a 4–8 week block, nutrition must rise with it.

If volume and intensity increase, carbohydrate intake should increase to match the rising energy cost. If there’s a block with higher resulting muscular damage — heavy eccentric work, high workloads — then protein may need to rise. Total calories usually need to climb across the mesocycle so athletes continue performing at the required level.”

This mirrors the carbohydrate periodisation literature, which emphasises adjusting carbohydrate availability according to training load to optimise performance and adaptation (Hawley & Leckey, 2015).

AI: What do you observe in semi-professional athletes? Where do they tend to go wrong?

Alex:

“In my experience, semi-professional athletes often hold themselves together very well with training and sleep. They train hard. They’re disciplined. But their nutrition falls apart because they don’t have professional guidance.

I’ve seen athletes dominate pre-season because they’re eating properly — high carbohydrate availability, consistent fuelling, and wanting to get in shape for season, good recovery nutrition is there too. But when the season starts, life gets busy, habits slip, and they stop prioritising performance-based nutrition as seasonal demand progresses.

They skip carbohydrate loading. They drop into more 'cheat' meals (I hate that term) during the week. They think it won’t matter — and then they fall apart on performance day, when it matters most! It’s not the training. It’s the fuelling. The structure simply wasn’t upheld when it mattered most.”

This matches research showing sub-elite athletes commonly under-fuel carbohydrate needs and fail to adjust intake to match training demands (Stellingwerff et al., 2007).

AI: For athletes looking to apply nutritional periodisation, what are the most impactful steps?

Alex:

“First, understand your training block, and what is demanded of you. If the workload is rising, carbohydrate intake must rise with it.
Second, identify the key session of the day and fuel specifically for that session.
Third, treat post-session carbohydrate as essential, especially if you train again within 24 hours.
Finally, stay consistent. Athletes aren’t worn down by catastrophic mistakes; it’s the small lapses repeated chronically that undermine performance.”

These steps reflect the core themes of modern sports nutrition frameworks, from carbohydrate periodisation to recovery optimisation (Burke et al., 2011; Impey et al., 2018).

Conclusion

Nutritional periodisation is one of the most reliable yet underutilised performance enhancers available to athletes. Training load fluctuates. Stress fluctuates. Recovery needs fluctuate. Nutrition must fluctuate too.

When athletes align their fuelling with the demands of each training block — and maintain that structure consistently — performance becomes predictable, robust, and repeatable.

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References

Aragon, A.A. & Schoenfeld, B.J. (2013) ‘Nutrient timing revisited: is there a post-exercise anabolic window?’, Journal of the International Society of Sports Nutrition, 10(1).

Burke, L.M., Hawley, J.A., Wong, S.H.S. & Jeukendrup, A.E. (2011) ‘Carbohydrates for training and competition’, Journal of Sports Sciences, 29(S1), pp. S17–S27.

Hawley, J.A. & Leckey, J.J. (2015) ‘Carbohydrate dependence during prolonged, intense endurance exercise’, Sports Medicine, 45(1).

Impey, S.G. et al. (2018) ‘Fuel for the work required: a theoretical framework for carbohydrate periodization and the glycogen threshold hypothesis’, Sports Medicine, 48(5).

Stellingwerff, T. et al. (2007) ‘Nutritional strategies to optimize training and racing in middle-distance athletes’, Journal of Sports Sciences, 25(sup1).

Thomas, D.T., Erdman, K.A. & Burke, L.M. (2016) ‘Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance’, Journal of the Academy of Nutrition and Dietetics, 116(3).