Freediving Nutrition for Deep Diving: The Empty Diver Myth

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Anthony Feoutis

AIDA & Molchanovs Instructor Trainer

He is the founder of The Depth Collector and VD Freediving Taiwan. With over a decade of experience, he focuses on solving real-world freediving problems, from equalization to depth adaptation, using practical, field-tested methods.

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This article was inspired by the AIDA seminar Nutrition & Supplements in Freediving: Perceived Effects vs. What Actually Works, presented by Prof. Dr. Marija Andjelkovic and Prof. Dr. Nenad Dikic. It is also shaped by my own experience as a freediving instructor and coach, and by the ideas I developed in my book Fueling for Depth: Nutrition for Freediving Performance, Recovery, and Focus. 

Hey, you reading this: I am not a doctor, and what follows is not medical advice.

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Freedivers are weird. Beautifully weird, but weird. My mum has had years to make peace with it.

We train like athletes, meditate like monks, or at least pretend to, obsess over oxygen and carbon dioxide, act like experts in human physiology, and yet many of us still have no real idea how to fuel ourselves properly for deep training.

I have lost count of how many times I have seen freedivers show up before a deep session having eaten nothing, drunk almost nothing, and proudly announcing, “I want to feel light for my PB.”

And every time, I cannot help thinking out loud:

“Light, my ass.”

This is what I call the empty diver myth: the idea that the emptier the diver, the better the dive. Empty stomach, empty bladder, empty bottle, empty calories, and sometimes, unfortunately, an empty brain trying to pretend this is elite preparation.

But nope.

It is not.

Freediving might look calm from the outside, but it still places real demands on your body and brain. You are dealing with pressure, movement, equalization, stress, CO₂, and all of it without breathing.

That requires energy.

I have been studying sports nutrition and trying to understand how the body responds during breath-hold diving. The more I learn, the less I understand how anyone can think deep diving on low battery is a good idea.

The body needs fuel to do its job.

Duh.

You would not set off on a long drive with an empty tank, so why approach a deep dive any differently?

Somehow, in freediving culture, “do not eat too much” became “do not eat at all.” “Stay light” became “starve yourself.” “Do not drink too much” became “arrive dehydrated.” Then we dressed the whole thing in discipline, fake expertise, and half-understood physiology.

And honestly, I cannot stand the freediving guru act anymore. The fake spirituality. The mysterious voice. The “I am so connected with the ocean” theater. The idea that every bad preparation choice becomes wisdom if you say it slowly enough. Freediving is already deep, beautiful, and intense. We do not need to cover bad physiology with incense smoke.

That is pure BS.

You want to eat before diving, but do it early enough for the food to be digested and useful, not sitting in your stomach like dead weight. The goal is to fuel your body without disturbing your dive.

And that comes down to timing.

Of course, that timing depends on what you eat. A banana, a small bowl of rice, or a slice of toast will not behave like a Double Whopper with extra cheese sitting in your stomach.

Extreme example, yes. But you get the idea.

Digestion time, stomach comfort, and glycemic index all matter.

To be clear, I am not saying fasting has no place in freediving. Fasting can work very well for static apnea, and I will probably write a full article about that one day, because it was part of my preparation for a 7-minute-plus STA. But static apnea and depth diving are not the same animal.

Lying still at the surface of a pool is one thing. Using your muscles to dive to 70 meters and come back up is a completely different story.

There is a little truth inside the empty diver myth. That is why it survives. A lighter stomach can feel better. Eating too close to a max dive can ruin relaxation. Heavy, greasy, spicy, high-fiber food before depth training is not smart.

But the opposite extreme is not intelligence. A starving brain is not a calm brain. An underfueled body is not an optimized body.

Freediving is already hard enough. We do not need to make it harder by starving the brain, drying the blood, worshipping supplements, and pretending physiology does not apply because we wear long fins.

Freediving Is Not a Normal Sport

Freediving does not fit neatly into normal sports categories. It is not pure endurance, even if depth and dynamic require endurance. It is not pure strength, even if constant weight, CNF, monofin, safety work, and repeated dives demand strength. It is not only technique, even if technique is everything. It is not only mental control, even if the mind can destroy a dive before the body even starts.

Freediving is a sport where you do not breathe. That changes the rules.

A runner breathes. A cyclist breathes. A swimmer breathes between strokes. A fighter breathes under pressure. Even a weightlifter only holds the breath for a short effort.

A freediver shuts the door.

No inhale. No exhale. No fresh oxygen coming in. No CO₂ leaving the body.

You become a closed system, and inside that system, every bit of stored energy matters.

During a breath-hold, oxygen drops, CO₂ rises, acidity changes, blood flow shifts, and the nervous system changes gear. The spleen may contract. The muscles change how they produce energy. The brain must remain calm while the body is slowly increasing the volume of its complaint.

And then you hear some freedivers say, “No need for breakfast. It is not like I am working out.”

Come on. Really?

You are doing one of the strangest athletic tasks on earth. You are asking your body to perform while refusing it the chance to breathe.

Yes, freediving is different from running and cycling. No, freedivers are not exempt from biology.

Your brain still needs fuel. Your muscles still need fuel. Your blood volume still matters. Your nervous system still reacts to stress. Your body still pays the bill.

And the deeper you go into performance, the more expensive that bill becomes.

Your Brain Is Part of the Dive

We talk about oxygen all the time.

Oxygen saturation. Oxygen conservation. Oxygen efficiency. Hypoxia. Blackout. Recovery breathing. Spleen contraction. Blood shift.

Good. We should talk about oxygen.

But sometimes we forget the most important oxygen consumer in the whole story: the brain.

The brain controls the dive plan. It decides when to turn. It manages discomfort when CO₂ is rising and contractions begin. It keeps technique clean when the body starts complaining. It handles equalization and, on a good day, stops you from doing something stupid.

For the ones who have one, of course.

Even though the brain represents only about 2% of total body weight, it uses around 20% of the body’s oxygen supply and roughly 25% of its glucose. It relies on this constant supply to produce ATP, the energy currency that allows nerve cells to function. Just in case you do not know, glucose comes from the food you eat.

In simple terms, your brain burns energy to fire electrical signals, recycle neurotransmitters, maintain its cells, process stress, control movement, and keep you from turning a deep dive into an underwater circus.

It is a high-maintenance organ.

I was stunned, to discover that roughly a quarter of the glucose I consume is used by my brain just to keep it functioning properly.  

So if you do not eat enough, what do you think happens?

A freediver who has not eaten will have low energy availability. Concentration, decision-making, emotional control, and motor control all suffer.

That matters.

It matters because freediving is not just floating down and coming back. It is a neurological, metabolic, technical, and psychological task performed in one of the most extreme environments on Earth. 

So eat.

Carbohydrates Are Not the Enemy

Carbohydrates have been treated like criminals for years. Too many diet gurus, keto prophets, fasting warriors, and influencers with abs but no context have convinced athletes that carbs are weak, dirty, outdated, or somehow suspicious.

Freediving has its own version of this nonsense. Some freedivers think carbohydrates will make them heavy, inflamed, too normal, too much like land athletes.

Well, in addition to being a freediver, I also train as a triathlete. And I can tell you this: you will not find many serious endurance athletes on planet Earth who will tell you that carbohydrates are useless.

Let me be clear: carbs are awesome.

Carbohydrates help replenish your muscles' glycogen stores. And guess what your legs rely on when the dive gets serious? Vasoconstriction kicks in, blood flow to the limbs is reduced, and you still need to fin back to the surface?

Yep.

Glycogen.

This does not mean you need to eat a mountain of pasta before a dive. Please do not. But it does mean that a well-timed carbohydrate meal can be one of a deep diver’s best friends.

Poor timing is the enemy. Too much volume is the enemy. Heavy food before diving is the enemy. Carbohydrates are not.

Hydration: The Invisible Killer of Good Dives

Now let us talk about the other proud mistake: not drinking enough.

The water lies to you.

You are in the ocean, so you think you are not sweating.

Wroooong.

You sweat in a wetsuit. You lose moisture through snorkel breathing. You lose fluid under the sun, during warm-ups, during stress, and during repeated dives. Because you are surrounded by water, you forget you are drying up.

By Poseidon, drink.

Dehydration is just bad logistics. All you need to do is drop a bottle of water in your buoy and actually use it.

As mentioned before, freedivers love talking about oxygen. But do you know what carries oxygen around the body?

Blood.

So blood volume and blood quality matter. When you are dehydrated, your blood becomes thicker, or more viscous, because there is less plasma relative to red blood cells. This reduces circulation efficiency and forces your heart to work harder to push thicker blood through your vessels. Oxygen delivery becomes less effective, and your system has to compensate. Thermoregulation gets worse. Mental clarity drops. Fatigue rises. Cramps, headaches, and nausea become more likely.

And then the freediver says, “I don’t know why I felt bad today.”

Yeah. No shit.

Check urine color. Drink regularly during the day. Use electrolytes when sessions are hot, long, or repeated. Do not wait until you are desperately thirsty.

Supplements: The Candy Shop of Athlete Insecurity

A supplement cabinet full of mystery powders is not a training system. It is just another way to gamble with your performance and call it science.

Now we enter the swamp: supplements.

Every sport has its supplement circus, and freediving is no exception. Actually, freedivers are perfect customers because we chase very specific feelings: calmness, lower heart rate, oxygen efficiency, CO₂ tolerance, relaxation, fewer contractions, better sleep, better recovery, sharper focus, less inflammation, more control. The list can go on forever.

Sell a freediver a normal gym pre-workout and maybe they ignore it. Sell a freediver “mitochondrial oxygen efficiency,” “parasympathetic activation,” “deep relaxation,” or “CO₂ buffering,” and suddenly the credit card comes out.

This does not mean supplements are useless. Some can be useful. But supplements are tools, not magic. They are not a substitute for training, food, sleep, recovery, or common sense.

Before asking which supplement you need, ask better questions.

Do you eat properly? Do you hydrate properly? Do you sleep enough? Do you take time to recover from training? Do you follow an intelligent plan?

If the answer is no, keep your money. You do not need another capsule. You need a better system.

The Anti-Doping Trap

There is another reason freedivers need to stop treating supplements like harmless candy: anti-doping risk.

Most athletes think doping problems come from people cheating on purpose. Steroids, EPO, secret injections, dirty doctors, villains in tracksuits. Yes, that exists. But a much more boring trap is sitting on the shelf of every supplement shop.

 Labels can be incomplete. Multi-ingredient products can hide substances you do not understand. Some products are made in facilities where cross-contamination is possible. And in anti-doping, “I did not know” may be emotionally true, but it may not protect you.

If you compete, you need to think like an adult.

Use simple products from serious brands. Avoid ridiculous pre-workouts, fat burners, testosterone boosters, “vitality” formulas, and anything with a giant proprietary blend. Keep photos of the label, batch number, receipt, and packaging. If you would not be comfortable defending that supplement before an anti-doping panel, maybe leave it on the shelf.

A freediver does not need to be paranoid.

But a competitive freediver cannot afford to be naive.

The Real Freediving Nutrition Hierarchy

First, real food. If your diet is chaotic, fix the plate before buying capsules.

Second, hydration. If you are dehydrated, beetroot juice will not save you. Check your urine, drink water regularly, and use electrolytes when needed.

Third, quality sleep. No supplement beats chronic sleep debt.

Fourth, training quality. If your technique is off, your relaxation is not really there, your progression feels random, and your training plan is all over the place, magnesium is not going to take you deeper.

Fifth, medical testing. If you suspect a deficiency, test. Do not guess.

Sixth, targeted supplements. Only then should you consider supplements, and only with a clear reason.

A Deeper Guide: Fueling for Depth

This article is only the surface.

Freediving nutrition deserves more than a few rules and a couple of angry sentences. That is why I wrote Fueling for Depth: Nutrition for Freediving Performance, Recovery, and Focus.

If you want to understand how to eat, hydrate, recover, and think about supplements as a freediver, the book goes deeper into the practical side of all of this.

Fueling for Depth: Nutrition for Freediving Performance, Recovery, and Focus is available on Amazon:

https://www.amazon.com/dp/B0GV3H9RSP

Kill the Empty Diver Myth

The empty diver myth feels pure. That is why people love it. Eat less, drink less, feel light, feel disciplined, feel ready. It is simple, seductive, and wrong when pushed too far.

Freediving performance is built from preparation: technique, equalization mastery, mental control, physical preparation, breathing, nutrition, recovery, and safety.

There is nothing heroic about arriving underfed, dehydrated, and proud of it. There is nothing spiritual about making your brain work harder than necessary. There is nothing advanced about using five supplements when you have not even figured out your breakfast.

If your goal is to dive deep, then nutrition is not optional. It is part of your training, part of your preparation, part of your performance.

Test everything in training. Keep records. Learn what works for you. Not from boat chit-chat between dives, not from the loudest person on the buoy, not from whatever your dive buddy swears is magic. Your body, your digestion, your nervous system, your recovery, and your dive history all matter.

The best freediving nutrition plan is the one that lets you dive calm, think clearly, recover well, stay healthy, and come back tomorrow.

Freediving is not a ritual of self-denial. It is a performance under pressure, where your brain, your body, and your decisions all have to work when it matters.

Eat. Drink. Go down ready.

And come back stronger.