We talk endlessly about…
VO₂max.
Lactate.
Training paces
Heart rate zones
We slice performance into metrics and sub-metrics and optimization frameworks. And all of that is useful. Necessary, even. But underneath all of it - beneath the physiology, beneath the psychology, beneath the training plans - there is something more fundamental:
Energy.
Not calories in the simplistic input-output way we usually consider them. Not your daily “macros”. But energy as a finite currency. A budget. An overall capacity of the athlete that can be directed well or mismanaged.
In this conversation with Aitor Viribay, we kept circling back to a deceptively simple idea: Energy is not limitless. And if that’s true, then performance becomes less about “spending more” and more about building more while allocating what you have wisely.
That’s a subtle but profound shift.
Aitor works at the absolute highest levels of endurance sport — Tour de France riders, ultra-distance athletes, competitors operating at the edge of what human metabolism can sustain. It would have been easy for this conversation to revolve entirely around fueling protocols and carbohydrate oxidation rates for these athletes. And yes, we discussed those 😊
But what struck me most was how often we drifted into bigger, almost philosophical, territory.
Debt.
Capacity.
Adaptation.
Uncertainty.
At one point, Aitor used a financial analogy that I think will resonate far beyond sport. You can drive the Lamborghini without having the money. But that’s called debt. And eventually, the bank shows up with the bill.
The body works the same way.
You can overspend training load.
You can overspend psychological stress.
You can overspend social comparison and external validation.
You can even overspend carbohydrate intake without the mitochondrial capacity to use it.For a while, it might look impressive. But eventually, the bill arrives.
One of the most important themes in this discussion was the order of operations.
Modern culture wants hacks. It wants fueling strategies before it wants fitness. It wants 120 grams per hour before it wants 10 years of aerobic base. It wants metabolic flexibility through food restriction rather than through movement.
But, as Aitor points out…
“mitochondria don’t grow because you eat avocados". They grow because you move. Because you stress the system. Because you created demand and then recovered from it.Capacity first. Resources second.
That hierarchy matters.
Fueling is powerful. In the right context, it’s performance-defining. But fueling without capacity is noise. Or worse — it’s additional stress layered onto a system that already lacks adaptability.
We also explored something that doesn’t get nearly enough attention in sport science: the energetic cost of modern life.
The brain is expensive. Uncertainty is expensive. Social comparison is expensive.
When you’re arguing with your spouse, worrying about contracts, refreshing social media, or trying to live inside the gap between expectations and capacity, that energy isn’t free. It doesn’t exist in a separate psychological silo. It shows up in the physiology. In the tolerance to training. In recovery. In decision-making under fatigue.
The highest performance environments don’t just add more inputs. They remove noise. They reduce uncertainty. They conserve energy for what matters.
That may be one of the most transferable lessons from the Tour de France to everyday life.
We closed on metabolic flexibility — a term that is often misunderstood.
Metabolic Flexibility is not about restriction. It’s about building range & using the right substrate at the right time.
It’s the ability to flow between substrates depending on the demands placed upon you. To burn predominantly fat at low intensities and shift decisively into carbohydrate when the moment calls for it. To be metabolically calm when nothing is required and explosively responsive when everything is.
That adaptability is not built through dogma. It’s built through exposure. Through intelligent intensity distribution. Through respecting the energy budget.
And ultimately, through humility.
Managing your energy is managing your life.
That’s true whether you’re racing the Tour de France or simply trying to show up well for your family and your work.
We hope that the conversation with Aitor strikes you in the same profound way that it did us, and hopefully leads to you examining your own energy in more depth…
What are you currently working with?
Does your current nutrition reflect that?
Where are your current “energy leaks”
How can you build more energy in your life?
If you’d like to go even deeper into the concepts of energy budgets, fueling limits, capacity building, and the psychology of performance mentioned in the podcast, please check out Iñaki de la Parra ‘s interview with Aitor below…
