7 Hyrox Nutrition Mistakes That Are Killing Your Performance

You've done the training. The sled sessions. The wall ball EMOMs. The 8km run simulations. But on race day, something doesn't click.

You bonk at station 6. Your legs turn to lead on the farmers carry. You finish minutes slower than your training times suggested.

The problem usually isn't fitness. It's nutrition. Here are the 7 most common Hyrox nutrition mistakes — and how to fix them.

This is the biggest mistake, and it's epidemic in the Hyrox community.

Many Hyrox athletes come from gym culture or body composition-focused backgrounds. They're used to tracking calories to stay lean, limiting carbs, and worrying about "eating too much."

The result? Chronic under-fueling that kills training adaptations, tanks recovery, and leaves you depleted on race day.

• Signs: Tired in the afternoon, surviving on coffee, poor recovery between sessions, declining performance despite training
• The fix: Hyrox training demands 15-17 calories per pound of body weight. Track for a week — most athletes are shocked how little they're actually eating.
• Use MAVR to calculate your actual needs based on training load

Carbs are not the enemy. For Hyrox athletes, they're the primary fuel source for both the running segments and the high-intensity stations.

If you're eating 150g carbs per day while training 6-8 hours per week, you're running on empty. Your glycogen stores are perpetually depleted, and your performance suffers.

• Signs: Energy crashes, needing caffeine to get through workouts, poor high-intensity performance, slow recovery
• The fix: Aim for 4-7g carbs per kg body weight daily, depending on training volume
• For a 70kg athlete training moderately: 350-420g carbs per day

A 2026 research review found that 40-50% of recreationally active people start exercise already dehydrated. For Hyrox athletes, that's a recipe for disaster.

Even mild dehydration (2% body weight loss) increases heart rate, perceived effort, and core temperature. At the sled push — when you're already maxing out — that dehydration tax becomes brutal.

• Signs: Dark urine, headaches after training, cramping, rapid heart rate for easy effort, brain fog
• The fix: Hydrate consistently the day before (2.5-3.5L), pre-load with electrolytes morning of, and drink 150-250ml in each Roxzone during the race
• Don't wait until you're thirsty — by then you're already dehydrated

You wouldn't race in new shoes. So why would you race with untested nutrition?

Many athletes "dial in" their nutrition during race week — trying new gels, new pre-race meals, new timing strategies. Then they wonder why they spend half the race fighting GI distress.

• Signs: GI issues on race day that didn't happen in training, cramping, bloating, "bathroom emergencies"
• The fix: Practice your exact race day nutrition in training. Every long simulation should include your pre-race meal, timing, and any during-race fuel.
• Test foods 4-6 weeks before race day, not the week before

Race week nerves hit and suddenly you're eating "super clean" — chicken breast, broccoli, no carbs after 6pm. Or you swing the other way and carb load with massive pasta dinners that leave you bloated.

Both extremes cause problems. Your gut needs consistency.

• Signs: Bloating, GI issues, feeling "off" on race morning, constipation or the opposite
• The fix: Keep eating your normal foods, just shift the ratios. More carbs, less fiber, moderate protein, low fat. Same foods you've been eating, different proportions.
• Carb loading doesn't mean stuffing yourself — it means strategic increase over 24-36 hours

Eating too close to race start means running with a full stomach, blood diverted to digestion, and potential nausea at the first sled push. Eating too early means depleted blood sugar and low energy by station 4.

• Signs: Nausea, side stitches, feeling sluggish, energy crash mid-race
• The fix: Main meal 3-4 hours before. Small carb snack 60-90 minutes before. Optional top-up 15-30 minutes before.
• Work backwards from your start time and set alarms

Caffeine can boost performance — but more isn't better. Overdoing it causes jitters, GI distress, anxiety, and can actually hurt performance.

• Signs: Racing heart before the race even starts, shaky hands, stomach cramping, anxiety that feels excessive
• The fix: Stick to your normal caffeine routine. If you want a performance boost, research suggests 3-6mg/kg body weight 30-60 minutes before — but only if you've tested it in training.
• For a 70kg athlete: 200-400mg (roughly 2-4 cups of coffee). Don't exceed what you've practiced.

MAVR is built to solve exactly these problems. Instead of guessing or making spreadsheets, you get science-backed guidance that adapts to your training.

• Calculates your daily calorie and macro targets based on actual training load (fixes #1 and #2)
• Tracks hydration and adjusts for conditions (fixes #3)
• Helps you build and test race day nutrition in advance (fixes #4)
• Provides carb loading guidance that's gradual, not extreme (fixes #5)
• Builds meal timing plans based on your race start time (fixes #6)
• Supports Hyrox-specific workout types so your fueling matches your training

The performance you've built through training is real. Don't let nutrition mistakes steal it on race day.