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HYROX Race Day Nutrition Calculator

Race day fuel plan based on your target time and body

Your Race Day Info

Race day fuel plan based on your target time and body

Used to estimate calorie burn, carb targets, and caffeine range.

Your realistic race goal determines the fueling density.

hr
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min

This anchors the meal and hydration timing windows.

Only select restrictions that should change the suggested meal examples.

How the Nutrition Calculator Works

HYROX race day nutrition follows a three-phase approach: pre-race loading, during-race fueling, and post-race recovery. The calculator personalizes each phase based on your bodyweight, target intensity (derived from your finish time goal), and dietary restrictions. All meal timing is anchored to your specific race start time so the plan is immediately actionable.

Pre-race nutrition is timed backwards from your start time. The 3-hour window focuses on a full carbohydrate-rich meal (2-3g carbs per kg bodyweight), the 1-hour window provides easily digestible carbs (0.5-1g per kg), and a final top-up gel or banana within 15 minutes of the start is optional for longer-duration athletes. Specific food suggestions are adjusted for vegan, gluten-free, and dairy-free diets.

During-race fueling depends on expected duration. Athletes finishing under 90 minutes typically need only water if properly fueled beforehand. For 90+ minute efforts, 30-60g of carbohydrate per hour from gels or sports drinks helps maintain blood glucose. Hydration targets are scaled to your bodyweight and adjusted for typical HYROX venue conditions.

Nutrition Mistakes That Cost Time

The most common nutrition mistake in HYROX is undereating on race morning out of nervousness or early start times. A 6 AM gun with no pre-race meal leaves athletes glycogen-depleted by station four or five, producing a dramatic slowdown in the second half. If your stomach is nervous, liquid calories (smoothie, sports drink, banana) are easier to consume than solid food and equally effective.

Trying new foods on race day is the second most common error. Race day is not the time to experiment with new gel brands, energy bars, or pre-workout supplements. Whatever you plan to consume on race morning should have been tested in at least two training sessions beforehand. The physiological stress of racing impairs GI tolerance, meaning foods that are fine in training may cause problems under race conditions.

Overhydrating before the race in an attempt to "top off" leads to discomfort during the early run segments. Drink normally the day before and morning of: approximately 500 ml in the 2 hours before the start is adequate for most athletes in temperate conditions. In hot weather, increase this by 200-300 ml and ensure sodium intake the previous evening to support fluid retention.

Frequently Asked Questions

Three hours before your start, eat a carbohydrate-rich meal with moderate protein and low fat. Examples include oatmeal with banana, rice with chicken, or toast with peanut butter. Avoid high-fiber foods and anything untested in training. One hour before, top off with easily digestible carbs like a banana or energy bar. Never try new foods on race day.
If your target time is under 90 minutes and you fueled properly beforehand, you likely do not need gels. For finish times of 90 minutes or longer, one or two gels taken during RoxZone transitions help maintain blood glucose and delay fatigue. Practice taking gels during training runs to confirm your stomach tolerates them before race day.
A typical HYROX race burns 800-1,500 kcal depending on bodyweight, intensity, and finish time. Heavier athletes and those in Pro division tend toward the higher end due to heavier loads. The calculator estimates your burn based on your specific bodyweight and target time using a MET-based model adjusted for HYROX's combined cardio and resistance demands.
Aim for 150-250 ml at each water station (roughly every 15-20 minutes). Avoid drinking large volumes at once as this causes discomfort during running. Pre-hydrate the day before and morning of the race with regular water plus electrolytes. Sodium and magnesium supplementation the night before is particularly effective for longer-duration athletes.
Light carb loading (increasing carbohydrate intake by 20-30% in the 2-3 days before the race) is beneficial for athletes expecting to race 90+ minutes. Full glycogen depletion protocols used for marathons are unnecessary and counterproductive. Focus on familiar high-carb meals rather than eating abnormally large volumes, which can cause GI distress on race morning.
Caffeine (3-6 mg per kg bodyweight) consumed 45-60 minutes before the race start is well-supported by sports science research. For a 75 kg athlete, that is 225-450 mg, approximately 2-4 cups of coffee. If you regularly consume caffeine, this amount is unlikely to cause jitteriness. Caffeine abstinence for 5-7 days before the race amplifies the effect but is optional.
Within 30 minutes of finishing, consume 20-30g protein and 60-80g carbohydrates to initiate muscle repair and glycogen replenishment. Chocolate milk, a protein shake with a banana, or a full meal with protein and carbs all work. Rehydrate with 1.5x the fluid you estimate losing (urine color is a practical guide). Most athletes need 48-72 hours of easy training before returning to full intensity.

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