- HYROX is eight rounds, each a 1 km run followed by one functional workout station, so your fuelling has to survive 8 km of running with 8 loaded stations woven through it.
- On a training day, the sourced daily carbohydrate range for an athlete doing moderate intense training is 5 to 8 g per kg of body weight (Kerksick et al., 2018).
- Whether you need anything at all mid-race depends on how long your race is, and the two published frameworks disagree about where a roughly hour-and-a-half event sits.
- If you do carry fuel, it has to be on you from the start. Taking anything from a spectator carries a 2-minute penalty per infringement.
- Hydration is a personal number, not a universal one. The NATA position statement's sweat-rate equation gives you yours after one training session.
- Nothing new on race day, and that includes the gut. Stomach comfort improves with practice, and the adaptation shows up within days.
Most HYROX fuelling advice gives you a confident number and no source. This guide does the opposite: every quantity below is attributed to the paper or position stand that states it, and where two respected sources disagree, you get both. The short version: eat familiar carbohydrate-led food in the hours before your wave, train your gut long before race week, work out your own sweat rate, and get carbohydrate back in fast afterwards.
What a HYROX race actually asks you to fuel
HYROX is eight rounds, each a 1 km run followed by one functional workout station. That is 8 km of running in total, broken up by 8 stations that are anything but a rest. You push 335 lb (152 kg) on the sled push in Open Men, carry 2 x 35 lb (16 kg) per hand on the farmers carry in Open Women, lunge under 44 lb (20 kg), and finish on 100 wall balls with legs that have already done everything else. The full load matrix by division sits on our weight standards tool.
That mix matters because it is neither a pure endurance event nor a pure strength one. Kerksick et al. (2018), in the International Society of Sports Nutrition's review update, make the general point that high-intensity bouts above 70% of VO2max extending beyond 90 minutes challenge both fuel supply and fluid regulation. A HYROX race lives near that boundary, which is why the advice splits.
How long is your race, and why the answer changes the advice
The official HYROX US FAQ states that the average HYROX finisher time in 2024/2025 was 1.5 hours, compares the event to a sprint triathlon or a fast half marathon, and notes there is no time limit. Treat that average as an average: it hides an enormous spread across divisions, formats and experience levels, and the gap between the front of a Pro field and a first-timer runs to tens of minutes. Our breakdown of HYROX finish times by division shows where you actually sit. Fuel for your race, not the average one.
What to eat before a HYROX race: the short answer
Eat a familiar, carbohydrate-led meal two to four hours before your wave, lower in fat and fibre than your usual meal, then a small top-up closer to the start if your wave is early. Drink water to thirst. Eat nothing you have not already eaten before a hard training session. Whether you need anything during the race depends entirely on how long you expect to be out there.
The meal window, and why every guide gives a different number
Run a search and you will collect four incompatible answers. One sports dietitian writing for Centr, a company that sells its own HYROX training programs, gives 4 to 7 g per kg of daily carbohydrate, hydration only under 60 minutes, and 30 to 60 g of carbohydrate per hour beyond that. Elsewhere you will find 6 to 8 g/kg over 24 to 36 hours, 8 to 10 g/kg over 48 hours, or 1.5 to 2.5 g/kg three hours out. Among the pages we read while researching this guide, not one cited a position stand or a peer-reviewed paper for its figure.
Those numbers are not all wrong. They answer different questions. A daily intake figure, a two-day loading protocol and a single pre-race meal dose are three separate things, and all of them scale with training volume, so a number that fits a triple-session athlete is meaningless for someone training four hours a week. The sourced anchor is Kerksick et al. (2018), who put athletes in moderate intense training at 5 to 8 g of carbohydrate per kg per day and note that glycogen stores are best maximised at 8 to 12 g/kg/day. Pick the band that matches your actual week.
The one rule that is not a matter of opinion
The official HYROX US FAQ states you can only take water or energy gels with you if they are on your person from the start, and that athletes cannot accept any beverage or nutritional product from anyone, spectators included, except at the aid stations. The Singles rulebook treats taking anything from another person as outside assistance, which carries a 2-minute penalty per infringement. The logistics of the morning belong to our HYROX race day guide, and the rule detail to our HYROX rules explainer.
Fuelling the training block, not just the race
Race week gets all the attention and changes almost nothing. What you eat across a training block determines what is in the tank on the day. Kerksick et al. (2018) give three bands. General fitness with no performance goal needs roughly a normal mixed diet, which they describe as 45 to 55% carbohydrate (3 to 5 g/kg/day), 15 to 20% protein (0.8 to 1.2 g/kg/day) and 25 to 35% fat. Moderate intense training, defined as 2 to 3 hours a day, 5 to 6 times a week, needs 5 to 8 g/kg/day to maintain liver and muscle glycogen. High-volume training of 3 to 6 hours a day, 5 to 6 days a week, pushes that to 8 to 10 g/kg/day.
Most people preparing for a HYROX sit in that middle band, not the top one. If your week is four or five sessions of running, compromised running and strength work, the figure you are being given is 5 to 8 g/kg/day, not the loading one. Our HYROX training guide covers what that week should contain.
The same review is specific about food quality: most dietary carbohydrate should come from whole grains, vegetables and fruit, with refined sugars, starches and engineered sports nutrition products reserved for situations where glycogen resynthesis has to happen fast. Gels and sports drinks are tools for a narrow job, not a daily habit.
Protein, and the mistake hybrid athletes make with it
The ISSN position stand on protein and exercise (Jäger et al., 2017) is blunt about priorities for anyone doing a lot of endurance work: endurance athletes should focus on achieving adequate carbohydrate intake to promote optimal performance, and the addition of protein may help to offset muscle damage and promote recovery. Protein supports the training. It does not power it.
The numbers from that stand: 1.4 to 2.0 g of protein per kg of body weight per day is sufficient for most exercising individuals, delivered as 0.25 g/kg per serving or an absolute dose of 20 to 40 g, distributed evenly every 3 to 4 hours. Higher intakes of 2.3 to 3.1 g/kg/day are discussed only for retaining lean mass while in a calorie deficit, which applies if you are deliberately cutting weight and not otherwise.
The part nobody repeats is the cost of overdoing it. Inside that same position stand, Macdermid et al. are cited for a study in which trained cyclists spent seven days on a high-protein, moderate-carbohydrate diet (3.3 g/kg protein, 5.9 g/kg carbohydrate) and seven days on a typical endurance diet (1.3 and 7.9). On the higher-protein diet it took them 20% more time to complete a self-paced time trial. The mechanism is displacement, not harm: protein crowded out the carbohydrate fuelling the effort. Note that several authors of this position stand list commercial supplement affiliations on the paper.
Training the gut, the part nobody tells first timers
Jeukendrup (2017), reviewing gut training in athletes, reports that gastrointestinal problems are very common and that 30 to 50% of athletes experience them regularly. The correlated practices are unsurprising: fibre intake, fat intake, and highly concentrated carbohydrate solutions. That list is the real argument for the boring pre-race meal.
The encouraging finding is that stomach comfort is trainable. In Lambert et al., cited in that review, trained runners drank a carbohydrate-electrolyte solution at roughly their sweat rate during 90 minutes of running, and their stomach comfort improved significantly with practice, without any measurable change in the rate of gastric emptying. Comfort adapted; the plumbing did not.
Adaptation is also fast and specific. In Cunningham et al., supplementing a normal diet with glucose for three days significantly sped gastric emptying of a glucose test meal, while emptying of a protein drink was unchanged, and a high-fat diet accelerated emptying of fat but not of carbohydrate. Over a longer window, Cox et al. followed 16 endurance-trained cyclists for 28 days, with a high-carbohydrate group averaging 8.5 g/kg/day against a control at 5.3 g/kg/day, and saw improved exogenous carbohydrate oxidation, most likely through upregulated SGLT1 transporters.
Jeukendrup is careful about how far this goes. He states that no direct human studies exist on the SGLT1 time course, and that the fact transport capacity has hardly ever exceeded 60 g/h, even in individuals, may be a sign that improvements are not dramatic. Practise your race fuelling in full simulations, but do not expect it to double your capacity. Both Jeukendrup papers cited here were supported by the Gatorade Sports Science Institute, a division of PepsiCo. He was an employee of the institute at the time of the 2014 paper; for the 2017 paper he declares attending a GSSI expert panel meeting and receiving an honorarium.
Do you actually need to eat during a HYROX?
This is the question the whole article turns on, and the honest answer is that two respected frameworks put a HYROX race on opposite sides of a line. Jeukendrup (2014) sets out bands by duration. During exercise lasting approximately one hour, a mouth rinse or small amounts of carbohydrate can produce a performance benefit. For more prolonged exercise of 2 to 3 hours, a single carbohydrate source can be oxidised at rates up to approximately 60 g/h, and that is the recommendation. For ultra-endurance events the figure is around 90 g/h, and at that rate it must come from multiple transportable carbohydrates, glucose plus fructose or maltodextrin plus fructose, typically studied in 2:1 ratios, because otherwise carbohydrate accumulates in the intestine. His 2017 paper gives a similar but not identical framing, recommending up to about 60 g/h for exercise lasting up to 2 hours and around 90 g/h beyond that. A race around the hour-and-a-half mark sits inside the lower band under both.
Our race day guide reaches a compatible conclusion from a different position stand, which frames the threshold around bouts longer than 60 minutes at high intensity. Two frameworks, two starting points, roughly the same practical landing spot: a fast Pro race probably needs nothing, a longer first-timer race probably benefits from something small.
On dose, the strongest evidence in Jeukendrup (2014) is the multicentre study by Smith et al., which tested 12 beverages delivering 10 to 120 g of carbohydrate per hour across 51 cyclists and triathletes at four sites and found the greatest performance enhancement between 60 and 80 g per hour. That was cycling. Neither framework contains HYROX data or studies mixed strength-and-running events of this length. We are applying a general endurance framework, and saying so.
There is a second, quieter disagreement about the units. Kerksick et al. (2018) report that several reviews advocate roughly 0.7 g/kg/h in a 6 to 8% solution, a per-kilogram convention. Jeukendrup (2014) argues directly against it, stating there appears to be no correlation between body weight and exogenous carbohydrate oxidation because the limiting factor is absorption, and that there is no rationale for expressing carbohydrate recommendations per kilogram of body weight during exercise. Both are respectable sources, and we are not going to pretend one settled it.
Practically: if you carry anything, the runs are the only place you will comfortably swallow it, and each is 1000 m long. The ROXZONE, the central transition zone athletes run through between every run and station, is where water is available, at least once before or after each pass through it per the HYROX US FAQ, with a sports drink possibly available too. Plan around water and treat anything else as a bonus.
Gels, chews, drink or food
Jeukendrup (2014) is relaxed about format. The carbohydrate can come from a drink, a gel, or a low-fat, low-protein, low-fibre solid bar, selection is largely personal preference, and athletes can mix and match. One caveat from the same paper matters more in a hot hall than most people expect: solid foods and highly concentrated carbohydrate solutions have been shown to reduce fluid absorption. If you are already struggling to drink enough, a dense bar is working against you.
Hydration, as a number you can actually calculate
The National Athletic Trainers' Association position statement on fluid replacement (McDermott et al., 2017) is written for practitioners and grades its recommendations, which makes it unusually easy to quote precisely.
Performance may be compromised at modest levels of hydration loss, around 2%. Recommendation 7, graded Strength of Recommendation A, is to promote euhydration within 1% either side of baseline body mass before exercise and a body mass loss of less than 2% at the end. Recommendation 6, also grade A, is blunt in the other direction: hyperhydration confers no physiological or performance advantages and is not recommended outside specific circumstances under medical oversight, and it can lead to exercise-associated hyponatremia, defined as serum sodium below 135 mmol/L during or within 24 hours of activity, typically symptomatic below 130 mmol/L, and potentially fatal.
The headline recommendation, also grade A, is individualisation: sweat rate, thirst and fluid intake during exercise vary greatly between people, so fluid-maintenance recommendations need to be worked out per athlete. Which you can do yourself, once, with a scale.
Work out your own sweat rate. From the NATA statement's own table: sweat loss in litres equals body mass before exercise in kg, minus body mass after exercise in kg, plus the volume of fluid consumed during exercise in litres, minus urine volume in litres if any. Sweat rate in litres per hour is that sweat loss divided by the exercise duration in hours. Run it once after a full race simulation in conditions like your event, and you have a personal number instead of an internet one.
Two more details from the same statement. When drinking to thirst with fluids freely available, humans replace roughly two-thirds of sweat losses, so thirst alone tends to undershoot on a hot day. And on absorption: maintaining 400 to 600 mL of fluid in the stomach optimises gastric emptying, the optimal carbohydrate concentration for fluid absorption is between 3% and 8%, exercise above 80% of VO2max may decrease gastric emptying, and drinking around 200 mL every 15 to 20 minutes may be ideal. That last figure is hard to apply in a race where you pass water only periodically, which is another argument for starting properly hydrated rather than trying to catch up.
What to eat after a HYROX race
Recovery is a bigger topic than fuel, and our HYROX recovery guide covers soreness, sleep and getting back to training. The fuelling arithmetic is short.
Kerksick et al. (2018) are explicit about precedence: the absolute delivery of carbohydrate, more than 8 g/kg/day or at least 1.2 g per kg per hour for the first four hours into recovery, takes precedence over timing, over adding other macronutrients such as protein, and over carbohydrate type. They also describe combining a moderate carbohydrate dose of 0.8 g/kg/h with protein at 0.2 to 0.4 g/kg/h. McDermott et al. (2017) add that simultaneous carbohydrate and protein after exercise beats fluid alone for muscle and blood glucose recovery.
Translated: eat a real carbohydrate-heavy meal within the hour, put protein alongside it, and keep drinking. If you race or train hard again the next day, be deliberate about that four-hour window. If you do not, get food in and stop optimising.
HYROX nutrition: what the evidence actually says
Five questions, five sourced answers. Every figure below names the paper it came from, so you can check any of it yourself rather than taking our word for it.
| Question | What the source says | Source |
|---|---|---|
| Daily carbohydrate in training | 3 to 5 g/kg/day for general fitness, 5 to 8 g/kg/day for moderate intense training, 8 to 10 g/kg/day for high-volume training | Kerksick et al. (2018), ISSN review update |
| Carbohydrate to maximise glycogen | Stores are best maximised by a high-carbohydrate diet of 8 to 12 g/kg/day | Kerksick et al. (2018), ISSN review update |
| Carbohydrate during exercise | Around 1 h: mouth rinse or small amounts. Up to 2 to 3 h: up to about 60 g/h. Ultra-endurance: about 90 g/h from multiple transportable carbohydrates | Jeukendrup (2014), Sports Med |
| Daily protein | 1.4 to 2.0 g/kg/day for most exercising individuals, as 0.25 g/kg or 20 to 40 g per serving every 3 to 4 h | Jäger et al. (2017), ISSN position stand |
| Fluid loss limit | Start within 1% of baseline body mass, finish having lost less than 2% (Strength of Recommendation A) | McDermott et al. (2017), NATA position statement |
Watch: a coach's take on HYROX fuelling
Rich Ryan is a HYROX coach and competitive athlete, and this is a condensed walkthrough of how he approaches fuelling rather than a review of the literature. Treat it as a practitioner's working system, and cross-check any number against the papers listed at the end.
Check your own event. Rules on carrying fuel, aid stations and outside assistance can change by season and event, so confirm against the official rulebook for your race. RoxTribe is an independent community resource, not affiliated with HYROX, and nothing here is individual medical or dietetic advice.
HYROX nutrition: your questions answered
What should I eat before a HYROX race?
A familiar, carbohydrate-led meal a few hours before your wave, lower in fat and fibre than a normal meal, then water to thirst. Kerksick et al. (2018) put daily carbohydrate for athletes in moderate intense training at 5 to 8 g per kg. The rule that matters more than any number: nothing you have not already eaten before hard training.
How many carbs should I eat before HYROX?
None of the position stands cited here gives a single pre-race meal figure, which is why every guide gives a different one. Kerksick et al. (2018) report that muscle and liver glycogen stores are best maximised by a high-carbohydrate diet of 8 to 12 g per kg per day. That is a loading target across days, not a single meal, and it scales with your body mass and training load.
Should I carb load for HYROX?
Only if your normal intake sits well below the loading range. Kerksick et al. (2018) put maximal glycogen storage at 8 to 12 g of carbohydrate per kg per day, against 5 to 8 g/kg/day for ordinary moderate intense training. If you already sit near the top of the training range, extra loading days buy you much less than the internet suggests.
What should I eat the night before a HYROX?
A normal-sized, carbohydrate-led dinner you have eaten before, lower in fibre and fat than usual. Jeukendrup (2017) reports that fibre intake, fat intake and highly concentrated carbohydrate solutions all correlate with gastrointestinal problems in athletes, and that 30 to 50% of athletes get such problems regularly. The night before is not the night to experiment.
Do I need gels during a HYROX race?
It depends on how long you are out there. Jeukendrup (2014) suggests that at around an hour, a mouth rinse or small amounts of carbohydrate is enough, and that up to about 60 g per hour applies to longer bouts. The official HYROX US FAQ puts the 2024/2025 average finisher time at 1.5 hours, which straddles both bands.
Can you take gels during a HYROX race?
Yes, but only if they are on you from the start. The official HYROX US FAQ states you can carry water or energy gels only if they are on your person from the beginning, and that athletes cannot accept any beverage or nutritional product from anyone, spectators included, except at the aid stations. Taking one from a friend carries a 2-minute penalty per infringement.
What should I drink during a HYROX?
Water is what the organiser guarantees. The official HYROX US FAQ says water is made available at least once before or after each pass through the ROXZONE, and that a sports drink or other hydration product may also be available. Plan around water and treat anything else as a bonus.
Do I need electrolytes for HYROX?
That depends entirely on your own sweat losses, which vary enormously. The NATA position statement (McDermott et al., 2017) makes individualisation its strongest recommendation, noting that sweat rate, thirst and fluid intake during exercise all vary greatly between people. Measure your sweat rate over one full simulation before deciding you need anything beyond water.
What should I eat after a HYROX race?
Carbohydrate first, protein alongside it. Kerksick et al. (2018) report that delivering at least 1.2 g of carbohydrate per kg per hour across the first four hours takes precedence over timing, over carbohydrate type and over adding other macronutrients. McDermott et al. (2017) note that carbohydrate with protein beats fluid alone for muscle and blood glucose recovery.
How much protein do I need for HYROX training?
The ISSN position stand on protein (Jäger et al., 2017) puts 1.4 to 2.0 g per kg per day as sufficient for most exercising people, delivered as roughly 0.25 g/kg or 20 to 40 g per serving every three to four hours. The same stand is blunt that endurance athletes should prioritise carbohydrate, with protein there to offset muscle damage and aid recovery.
Why does my stomach hurt during HYROX?
Because the gut is a trainable organ and most people never train it. Jeukendrup (2017) reports 30 to 50% of athletes get regular gastrointestinal problems, and that in Lambert et al., runners' stomach comfort improved significantly with repeated practice at high drinking rates, without any measurable change in gastric emptying. Practise race fuelling in a full simulation.
References
- Official HYROX US FAQ. Primary source for the average finisher time and the rules on carrying water or gels and accepting nutrition during the race. Read 2026.
- Official HYROX Singles Rulebook, Season 26/27. Primary source for the station standards and the outside-assistance penalty.
- Jeukendrup A (2014). A Step Towards Personalized Sports Nutrition: Carbohydrate Intake During Exercise. Sports Med. Open access on PMC.
- Jeukendrup AE (2017). Training the Gut for Athletes. Sports Med. Open access on PMC.
- Jäger R, Kerksick CM, Campbell BI, et al. (2017). ISSN Position Stand: protein and exercise. J Int Soc Sports Nutr. Open access on PMC.
- Kerksick CM, Wilborn CD, Roberts MD, et al. (2018). ISSN exercise and sports nutrition review update. J Int Soc Sports Nutr. Open access on PMC.
- McDermott BP, Anderson SA, Armstrong LE, et al. (2017). NATA Position Statement: Fluid Replacement for the Physically Active. J Athl Train. Open access on PMC.
- Angie Asche, A dietitian's guide to HYROX nutrition, Centr (2025). A named sports dietitian's HYROX-specific guidance. Centr promotes its own HYROX training programs.