TLDR;
On Tuesday we broke down the physiology of health vs fitness and why a shredded body often hides a broken engine. Today is my personal coaching take on what happens when you stop chasing extreme aesthetics and focus on what actually makes you durable:
The aesthetic illusion: Having 7% body fat or visible abs looks great on Instagram, but in ultra running it usually means cold hands, dead legs, and a tanked endocrine system.
Fuel the work, not the mirror: If your training demands 50 to 100 km a week of trail pounding, you cannot eat like you're trying to step on a bodybuilding stage.
Health is durability: Real ultra fitness is built on deep sleep, hormonal stability, and adequate energy reserves—not starvation.
Physiology vs reality
On Tuesday, we looked at the difference between being healthy and being fit: how fitness is simply task-specific physical adaptation, while health is baseline systemic vitality (your hormones, immune function, and recovery).
On paper, everybody nods along and agrees.
In reality? Almost every runner I talk to has, at some point, fallen into the exact same trap.
We look at running culture, fitness influencers, or the lead pack at an ultra, and our brains instantly link being rail-thin with being fast. There is this unspoken obsession with getting as light and shredded as humanly possible, assuming that shaving off every ounce of fat will make you glide up mountain passes like Kilian Jornet.
The problem is though, reality does not work that way.
Because while power-to-weight ratio is a real physiological metric, chasing aesthetic leanness almost always ends up sabotaging the very engine you’re trying to build.
The cost of looking like a fitness model
I’ve seen this play out with so many athletes over the years.
A runner gets in great cardiovascular shape. They start dropping weight. Their race times improve for a couple of months, so they double down: they cut carbs, skip post-run meals to "stay in a fat-burning zone," and aim for that chiseled, vascular look.
For about eight to twelve weeks, they feel like superheroes.
And then the bill arrives.
First, their sleep turns to garbage. They wake up at 3:00 AM with racing hearts because cortisol (stress hormone) is spiked through the roof to keep blood sugar stable.
Then, their libido vanishes. Their resting body temperature plummets—they’re wearing a hoodie and gloves in a 21°C room because their thyroid function is down-regulated to conserve energy.
Finally, the nagging injuries start. That mild Achilles ache turns into full-blown tendinopathy, their bone density drops, and suddenly they're staring down an MRI for a tibial stress reaction.
They looked ridiculously fit. Their abs were sharp in race photos.
Underneath the surface, their body was running on fumes, tearing down its own connective tissue just to survive the mileage.
What actually matters on the trail
When you're 60 km into a mountain race and your quadriceps are screaming on a 15% technical descent, your body does not care whether you have visible veins on your stomach.
What your body cares about is:
Energy availability: Do you have enough glycogen and circulating energy to keep your brain focused and your central nervous system firing?
Structural durability: Are your bones, tendons, and muscles nourished enough to absorb thousands of high-impact footsteps without fracturing?
Hormonal balance: Can your endocrine system recover from 30 hours of continuous cardiovascular stress, or are you going to crash into non-functional overreaching for six months?
In endurance running, health is your insurance policy.
Fitness gives you the capacity to run hard today. Health is the cushion that keeps you from breaking when the training load gets heavy.
If you sacrifice your health—by starving yourself of fuel, ignoring sleep, or keeping your body fat at an unsustainable low—your fitness will eventually collapse right behind it.
The bottom line
Stop measuring your progress by what you see in the bathroom mirror under good overhead lighting.
Eat real food. Fuel your long runs with enough carbohydrates so your body doesn't eat its own muscle. Give yourself enough healthy body fat that your hormones stay balanced and you actually have energy to enjoy your life outside of running.
Being an ultra runner is about capability, resilience, and longevity.
Build an engine that can take a beating and keep going. The rest is just noise.
If you are trying to figure out how to fuel your mileage properly, avoid the common burnout trap, or want guidance building a sustainable training block that fits your life, you are always welcome to book a 1:1 call with me, completely free, no strings attached.