Triathlon Training Nutrition Guide


Swim, bike, run, and repeat. Seems simple, right? But if you think that’s all there is to triathlon training, think again—what you eat while you train is just as important as how you’re training.

“Nutrition is the fourth leg of any triathlon,” says triathlete Kim Mueller, R.D., owner of Fuel Factor athletic nutrition coaching in San Diego. “A healthy diet has to be part of your lifestyle before training can make an impact. You have to dial your nutrition in from the get-go.”

Whether you’re going for a sprint triathlon or an Ironman, your training regimen will have your body at its max. You’ll be burning through more energy than most people use in an entire day, and that means you need to eat more. But just like you need the right training plan to dominate the race, you also need the right fuel to power you through.

So we asked the experts for their best advice and put together a step-by-step nutrition guide that will bring your tri-performance to the next level.


Eat Real, Not Processed
Forget frozen pizzas and energy drinks. Processed foods contain all sorts of funky ingredients that can cause inflammation throughout your body, slowing your recovery time and weakening your immune system, Mueller says.

Since scrapping all processed foods is easier said than done, start small. At the grocery store, Mueller suggest skimming food labels before you hit the check out. If you don’t recognize an ingredient, don’t buy the food, she says. If you are feeling deprived, focus on adding whole foods like fruits, vegetables, and lean meats to your plate—rather than keeping processed ones at bay. Behavior psychologists have found that it is easier to add a behavior than to take one away.

Pack More Produce
“Focus on eating foods—especially produce—with a variety of colors. Try to hit all of the colors in the rainbow,” Mueller says. The colors of fruits and vegetables are clues as to what vitamins and phytochemicals they hold. Eat them all and you are guaranteeing yourself a wide range of antioxidants and nutrients to lessen the oxidative damage and inflammation caused by your training.

Fiber-rich fruits, vegetables, and whole grains (not white ones!) are also great sources of healthy carbs, which should be any triathlete’s best friend. Endurance athletes primarily run on stored energy—called glycogen—that’s converted from carbohydrates. The American College of Sports Medicine recommends that endurance athletes consume 2.7 to 4.5 grams of carbohydrates per pound of bodyweight each day. Three months out, when your workouts aren’t quite as grueling as they could be, you can stick to the lower half of that range. So a 150-pound man should be consuming about 405 to 540 grams of carbohydrates a day.

Take It Easy on Protein
While your prescription for protein does increase while training (it’s a great source of amino acids that can help rebuild muscles after a workout), fight the urge to go mow down on a T-bone every night, says Carmichael Training Systems coach Nick White, who helped Craig Alexander win two Ironman World Championships. You’re not a bodybuilder. You’re a triathlete. As such, you need about 0.5 to 0.8 grams of protein per pound of bodyweight, according to the American College of Sports Medicine. And again, it’s safe to shoot for the low end if your workouts aren’t particularly grueling, Mueller adds.

So, that same 150-pound man will need to consume between about 75 and 97.5 grams of protein three months out from the big race. Notice that’s far fewer grams of protein than carbohydates. White advises keeping your carb-to-protein ratio between 4:1 and 7:1. If you aren’t into lean meats for your protein fix, try out Greek yogurt, edamame, or skyr. Bonus: Many whole grains—such as quinoa and lentils—also contain ample supplies of protein for a one-two nutritional punch.


Fuel Your Workouts
As your workouts peak in intensity, you need even more carbohydrates to ensure proper glycogen storage and energy. Before any workout, fuel up with some whole food carbohydrates and follow your cool down with some more carbs and a bit of protein, White says.

However, if your workout lasts more than two hours, you shouldn’t wait until your workout is over to replenish your energy reserves in order to maintain intensity. “Your body only has so many calories saved up inside. You’ve got to replace them while you are exercising,” says White. During moderate- to high-level exercise, you’re burning between 500 to 1,000 calories per hour. And your body typically only stores about two hours’ or exercise worth of carbohydrates. Try eating sports gels or “beans” mid workout. They are calorie-rich sources of simple carbohydrates and are easy to consume mid workout, he says.

Feed Your Immune System
When your workouts peak in intensity, so does the oxidative damage in your body and your need to protect yourself from illness. If you hit all of the colors of the rainbow with your food choices—literally—by eating a lot of produce with a range of antioxidants, you will prevent the majority of the sniffles, Mueller says.

If you find yourself still feeling run down or sick frequently, up your barriers with a multivitamin that includes Coenzyme Q10, which can be especially helpful in speeding recovery, suggests White. And no matter how busy your schedule is with long endurance workouts, you still need at least eight hours of sleep a night. Sleep gives your body needed time to recuperate from your workouts, he says.

Rehearse Race Day
Plan a few extra-long workouts so that you can experiment with different day-of nutrition options. While you should focus on carbohydrates for before, during, and after your workout, you’ll want to steer clear of fiber (more on that during your one-week-out plan), Mueller says. Remember the sports gels and beans you’ve been eating during workouts? They are perfect course companions.

Last but not least, before you begin your rehearsal workouts, you should weigh yourself. Then, once you complete your workouts, weigh yourself again. You should have sweat out no more than 2 to 3 percent of your total body weight. If you lose any more fluids, you’ll experience a significant drop in performance and can risk your health, she says. Adjust your day-of hydration plan accordingly. Write down whatever nutrition and hydration choices work for you in your training log so you’ll remember what to do come race day.


The morning of the race is too late to start thinking about your hydration strategy. Start putting back between 64 and 96 ounces of water a day based on your activity level. Keep water with you at all times and you’ll easily sip through your allotment in 24 hours, Mueller says. Another word to the wise: Lay off drinks that contain caffeine or alcohol, as they can actually cause dehydration.

A time-honored tradition of endurance athletes, carboloading allows your body to be packed full of glycogen on race day, so you’ll avoid running out of reserves and hitting the proverbial wall. Starting about three days before the race, start consuming about 3.5 to 4.5 grams of carbs per pound of body weight, Mueller advises. So if you weigh 150 pounds, consume between 525 and 675 grams of carbohydrates each day leading up to your race. Since you won’t be working out much—if at all—you can increase your glycogen concentration big time in a matter of days, she says.

Forget Fiber
Rather than munching fiber-rich carbohydrates like before, you should now focus on easily digestible simple carbohydrates that are low in fiber, so you don’t experience any digestive distress (there’s a reason some triathletes sport diapers) mid bike, run, or swim, Mueller says. You can now turn to simple—even white—grains such as white rice, white bread, and white potatoes. Fruits are safe as long as they do not contain seeds or tough, edible skins. She recommends bananas, mango, papaya, cantaloupe, and melons.


Fill Up Your Engine
Eat low-fiber carbohydrates and a small amount of protein to help stabilize your blood sugar despite skimping on fiber. A slice of plain toast with peanut butter, smoothie, pulp-free juice, yogurt, mango, or PureFit nutrition bar can all be part of a great pre-race breakfast, Mueller says. Don’t eat less than two hours before race time to prevent your digestive system from competing with the rest of your body for oxygen; it takes at least one hour to process every 200 to 300 calories you consume, she says.

Stay Focused on Your Plan
Now is not the time to take an interest in improv comedy. Execute everything—from your breakfast to your mid-race gel packs—just as you wrote them down in your training log a month ago, Mueller says. And no matter how eager you are to cross the finish line, don’t skip water pit stops. Not drinking enough water is the biggest nutritional mistake that triathletes make. Dehydration can lead to cramping, headaches, dizziness, and nausea, all of which can slow you down more than grabbing a cup from the sidelines, she says.

Refuel and Replenish
Despite the urge to head straight for the beer garden, your first line of liquid nutrition should be alcohol-free. While the American College of Sports Medicine recommends consuming 0.5 to 0.75 grams of carbohydrates per pound of body weight immediately after the race, it’s best to get the bulk of those carbs from a smoothie or sports drink so that you also replenish fluids. No matter how much water you drink during the race, you will be slightly dehydrated when you cross the finish line, Mueller says. They can also help to replenish sodium that you’ve sweated out.

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