21 Triathlon Race Week Nutrition Tips to Avoid Gut Issues!
“Hey, what should I eat during race week? I really don’t want gut issues during the race…”
If you’ve ever asked yourself that — or heard it from a buddy nervously counting gels the night before a race — this one’s for you.
Gut issues are probably the last thing you want to deal with on race day.
We all know that the right race nutrition matters, but what you do the week before might be just as important (if not more).
Let’s break it down, nice and simple.
Core Principles
Nothing New on Race Day
Perhaps the most important rule of race nutrition is also the simplest: don’t try anything new on race day.
That includes meals, sports drinks, supplements, gels, or energy chews — if it didn’t get tested in training, it doesn’t belong in your plan.
Your gastrointestinal system is extremely sensitive under stress, and unfamiliar foods or supplements can cause cramping, bloating, or worse during high-intensity efforts.
Race expos are fun, but they’re not the place to discover your new go-to product.
Even natural or “clean label” items can contain ingredients your body isn’t used to — like sugar alcohols or untested herbal extracts.
Stick to what your gut knows.
Predictability and routine are your best friends the week of your race.
Carb Loading & Low-Residue Nutrition
Start Carb Loading 2–3 Days Before the Race
Carbohydrate loading is designed to maximize muscle glycogen stores, the body’s primary fuel source for endurance exercise.
While some athletes believe in a “pasta party” the night before, that’s often too late — and too heavy — to be effective.
Instead, gradually increase your carbohydrate intake 2 to 3 days before race day while slightly reducing fats and fiber.
This approach helps promote glycogen saturation without overwhelming your digestive system.
Good carb-loading foods include white rice, plain pasta, white bread, ripe bananas, applesauce, and fruit juice. These are low in fiber, easy to digest, and help pack in energy without creating gastrointestinal residue.
Be careful not to overeat; the goal is to shift macronutrient balance, not add overall volume. Your meals should stay relatively normal in size — just higher in carbohydrates.
Reduce Fiber 24–36 Hours Before the Race
Fiber is essential for long-term health and digestion, but in the final 24 to 36 hours before a race, too much fiber can lead to bloating, gas, or urgent bathroom visits — all things you want to avoid.
Begin tapering your intake of fibrous vegetables, beans, lentils, and whole grains during this window.
Even “healthy” foods like raw salads and energy bars with oats or seeds should be minimized.
Stick to low-residue carbohydrates such as white rice, rice noodles, white bread, and fruit juices.
These are absorbed quickly and leave little behind in the digestive tract.
While fruits are generally a healthy choice, many of them are high in insoluble fiber and natural sugars that ferment in the gut.
If you want to include fruit, opt for peeled ripe bananas or small portions of stewed fruit or juice.
Apple juice, in particular, is a good option — it contains potassium, which helps with both glycogen storage and hydration.
Make Lunch Your Largest Meal the Day Before
Timing your biggest meal the day before the race can have a significant impact on how you feel on race morning.
Instead of loading up on dinner — which can interrupt sleep and sit heavy in the gut — eat your largest, carb-dominant meal at lunchtime.
This gives your body more time to digest, absorb, and store glycogen without leaving undigested food in your stomach overnight.
Dinner should still include carbohydrates, but keep the portion moderate. Focus on easily digestible foods, light sauces, and a comfortable serving size.
You want to wake up on race day feeling fueled and light, not overly full or sluggish.
Get expert coaching, tailored to your schedule, so you can train smarter, race stronger, and still have time for life.
Hydration & Electrolytes
Hydrate Consistently Throughout the Week
Optimal hydration starts days before your race — not the night before.
Aim to drink 2.5 to 3 liters of water per day in the days leading up to the race, depending on your size, sweat rate, and climate.
Rather than chugging water all at once, spread your intake evenly throughout the day.
Keeping a bottle with you is a simple but effective way to maintain this habit.
Hydration impacts much more than just thirst.
It affects muscle function, heart rate, digestion, and your ability to regulate temperature.
Starting the race in a hydrated state improves endurance, delays fatigue, and reduces the likelihood of cramping.
Prioritize Electrolytes, Especially Sodium
Electrolytes are essential for maintaining fluid balance, nerve function, and muscle contraction.
Sodium, in particular, plays a key role in helping the body retain water and transport glucose into cells.
During race week, include electrolytes daily — through hydration tablets, drink mixes, or lightly salting your meals.
If you’re training or racing in hot or humid conditions, or if you’re a “salty sweater” (evidenced by salt crusts on clothing or stinging eyes), electrolyte management becomes even more critical.
You may need to increase sodium intake slightly to ensure your body holds onto fluids and is better prepared for sweat losses.
Consider a Sodium Preload for Hot Races
If your race is expected to be hot or humid, consider implementing a sodium preload 12–24 hours before the event.
This usually involves drinking 1000–1500 mg of sodium mixed with water or a sports drink (such as LMNT or Skratch).
Research shows this can increase plasma volume, enhance thermoregulation, and reduce perceived exertion in the heat.
Add a Pinch of Salt to Your Bottles
In the final days before the race, especially if you’re a heavy sweater, add a small pinch of salt to each water bottle.
This helps retain more of the water you drink and supports steady sodium levels heading into the event.
Avoid Overhydration Before Bed
It’s common to overcompensate the night before a race by drinking large volumes of water, but this can backfire.
Excessive fluid intake too close to bedtime may interrupt your sleep due to frequent bathroom trips.
Cut off fluids about 1.5 to 2 hours before bed to ensure rest and optimal hydration balance.
Fueling Strategy & Logistics
Prepare Your Nutrition Plan in Advance
Plan your race-day nutrition in detail several days before the event.
Lay out your gels, chews, bottles, and anything else you’ll be using on the course.
Label them clearly, double-check quantities, and pack extra in case you drop something or unexpected delays.
This process eliminates last-minute stress and ensures you’re following a strategy that aligns with your training experience.
Create a Structured Fueling Schedule
Rather than waiting until you feel hungry or tired, use a time-based fueling plan.
For example, take a gel every 30 minutes on the bike, sip fluids every 10–15 minutes, and time your fuel intake around course landmarks like aid stations or transitions.
A structured plan helps keep energy levels stable, supports mental focus, and prevents the common pitfall of under-fueling early in the race.
Some fitness watches even let you create nutrition timers for during the race!
Label Nutrition by Timing, Not Just Flavor
Label your bottles, gels, and chews by when they’ll be used — for example, “T1,” “Mile 10,” or “Run Start.”
This small step reduces cognitive load and makes it easier to stick to your plan, especially when your focus is on pacing and effort.
If there is extra space on the packaging, I can also recommend adding some motivational quotes;)
Use a Carb + Sodium Drink on the Bike
A drink mix that includes carbohydrates and electrolytes is ideal for the bike leg.
This reduces reliance on solids, minimizes digestive stress, and ensures consistent fluid and energy intake.
Choose a concentration that works well in training, and test it at race intensity beforehand.
Take a Gel Before the Swim Start
Approximately 5–10 minutes before the swim, consume a gel to top off blood glucose and ensure you’re starting with readily available energy.
This can be especially helpful in longer races or if you’re prone to early fatigue.
Test Carb Sources in Training
Different athletes tolerate different types of carbohydrates.
Test both glucose-only and glucose-fructose blends during training to determine what works best for your gut and energy levels.
Efficient absorption and gut comfort are key.
Bring Your Own Race-Morning Meal
Never rely on hotel breakfasts or food vendors.
Bring your own familiar, pre-tested breakfast — something portable like a bagel with peanut butter, oatmeal, or rice cakes with honey.
Eat it at the same time you’ve practiced, ideally 2–3 hours before race start.
Visualize Your Fueling Plan
Mental preparation enhances execution.
In the days leading up to the race, visualize your fueling plan: when you’ll eat, where you’ll hydrate, and how you’ll respond if you miss a gel or feel off pace.
Practicing these scenarios mentally can make it easier to stay calm and focused when it counts.
Gut-Brain Connection & Recovery
Manage Nerves to Protect Digestion
Race-week stress can reduce appetite and delay gastric emptying.
Incorporate light movement, breathing exercises, or yoga to support digestion and reduce anxiety.
Don’t force large meals — focus on small, frequent meals with easy-to-digest carbs and lean proteins.
Eat Slowly and Mindfully
On the day before the race, slow down your eating.
Chew thoroughly, avoid rushing, and be aware of how your stomach feels.
This helps prevent bloating and promotes digestive efficiency.
Recover Immediately Post-Race
Recovery starts within the first 30–60 minutes after finishing.
Even if you’re not hungry, aim for a simple mix of carbs and protein — like a recovery shake or chocolate milk (my personal favourite).
This helps replenish glycogen, repair muscle tissue, and support the immune system.
Save the Celebration for Later
Once your stomach settles, feel free to enjoy that burger, fries, or post-race treat.
But in the immediate aftermath, prioritize nutrition that supports physiological recovery, not just appetite.
Get expert coaching, tailored to your schedule, so you can train smarter, race stronger, and still have time for life.
Wrapping Up
Race-week nutrition is about consistency, preparation, and minimizing variables.
Focus on what’s worked in training, stay disciplined with hydration and fueling, and approach each day with intention.
A well-executed race starts well before the gun goes off — and smart nutrition is a key part of that process.
Check out this post to learn more about how to fuel your triathlon training!
Frequently Asked Questions
What should I eat during an endurance race?
During an endurance race like a triathlon, your nutrition should focus on three things: carbohydrates, fluids, and electrolytes.
Carbohydrates are your body’s main energy source during prolonged exercise. Aim to consume 30–90 grams of carbohydrates per hour, depending on the race duration and what you’ve practiced in training. Shorter races (like sprint triathlons) may only require ~30–45 g/hr, while long-course events (like 70.3 or Ironman) can benefit from 60–90 g/hr using a combination of glucose and fructose sources (e.g., sports drinks, gels, chews).
Hydration should be ongoing and adjusted based on temperature, sweat rate, and race length. Most athletes do well with 400–750 ml of fluid per hour.
Electrolytes, especially sodium, should be consumed alongside fluids to replace what’s lost in sweat. This can come from sports drinks or salt capsules — target 300–700 mg of sodium per hour, though heavy sweaters may need more.
Pro tip: Start fueling early — don’t wait until you feel hungry or tired. Use a timer or course landmarks to stick to your plan.
What not to eat before a triathlon?
In the 24–36 hours before a triathlon, avoid foods that are high in fiber, fat, or unfamiliar. These can slow digestion, increase the risk of gastrointestinal distress, and cause discomfort during the race.
Specifically, avoid:
Raw vegetables (e.g., salads, broccoli, cauliflower)
Beans, lentils, and high-fiber grains (e.g., quinoa, whole wheat bread, oats)
Fried or greasy foods
Spicy dishes
Alcohol and carbonated beverages
New supplements or energy products you haven’t tested in training
Also, be cautious with dairy products if you’re sensitive to lactose, and reduce fruit intake in the final 24 hours — even though it’s healthy, the fructose and fiber can ferment in the gut.
Instead, focus on simple carbohydrates, small portions of lean protein, and low-residue meals like white rice, pasta, or bread.
How many days should you rest before a triathlon?
Most triathletes benefit from a taper period that includes reduced volume but maintained intensity. The number of rest days depends on the race distance, your training load, and your experience level:
Sprint Triathlon: 1–2 rest or very light days before the race is usually enough.
Olympic Distance: 2–3 days of reduced load and 1 complete rest day before race day.
70.3 / Ironman: 5–10 days of taper with 2–3 lighter days and at least 1–2 rest days before the race.
One complete rest day before the race is often ideal, but some athletes prefer a very short, low-intensity session (e.g., 15 minutes swim, bike, or jog) to stay loose.
Avoid high-intensity intervals or long workouts in the final 3–5 days. The goal is to show up fresh, sharp, and rested — not flat or fatigued.
Listen to your body, trust your training, and use race week to recover, fuel, and focus.
