The Ultimate Triathlete Diet Guide

There’s no doubt you’re familiar with the three disciplines of a triathlon: Swimming, cycling, and running. But there’s a fourth discipline that athletes often overlook, and it's nutrition. An optimal triathlon nutrition plan can be the difference between a PR and an upsetting finish. Build your endurance nutrition IQ with the tips below and get ready for your best tri season yet.

Your Daily Triathlon Diet

While race day nutrition is important, it’s what you eat outside of events that generally makes the biggest difference in health and performance. By focusing on a wholesome daily diet, you help your body maximize training adaptations and recovery throughout your season.

A nutritious triathlete diet doesn’t vary much from standard healthy eating recommendations. But you should anticipate eating more during the season and less during the off season to account for changes in energy output.

You can break your triathlon diet plan into three essential pillars. These concepts may sound easier in theory than in practice, but sticking with them will serve you well.

1. Eat high-quality meals and snacks made up of mostly whole foods.
2. Enjoy treats occasionally, but don’t overcompensate for your workouts. (In other words, avoid rationalizing eating an entire sleeve of cookies because you pounded the pavement—but it’s certainly okay to grab one or two cookies.)
3. Maintain a healthy weight while molding your body and exercises to meet the needs for swimming, cycling, and running.

Monitor Your Macros

Each of the three macronutrients (carbs, protein, and fat) serves an important purpose in a triathlete's diet. There’s no hard-and-fast rule on the exact amount of each macronutrient that your body needs. It varies based on your genetics, training regimen, and any medical conditions you might have.

Carbohydrates

Typically one would consume 45% to 65% of calories, or approximately 3 to 12 grams of carbohydrates per kilogram of body weight. However, for a person who participates in triathlon, even though the percentage may be correct, you should expect to be consuming 8 to 12 grams of carbs per kilogram of weight per day. As the training intensity and duration increase, you may be consuming closer to 12 grams per kilogram of weight.

Simple carbohydrates like bananas should be consumed at least 30 minutes prior to your workout. During intense exercise lasting longer than 60–90 minutes, try fast-absorbing carbohydrates like gels that replenish your electrolytes. For longer bouts of exercise, you can expect to consume 30 to 60 grams of carbohydrate in a electrolyte and fluid solution within each hour of training and event day.

Protein

Aim for 2 grams per kilogram of bodyweight when training. Timing is important. Since your body can't store protein, it should be consumed every 3-4 hours throughout the day, and ideally within two hours post-workout for recovery. In the evening, it is recommended to consume about 30-40 grams of protein from casein.

Fat

Aim for 20% to 35% of calories. Fat is important for nerve function, organ protection, and is a source of fatty acids. But if performance and achieving a new personal best time is vital, a high-fat low-carb diet can slow you down. When training, the calories leftover from the carbohydrate and protein needs will be fat.

Most triathletes will fare well using these recommended ranges. If you’re curious about how your macros compare to these numbers, try tracking your food for a few days via a website or phone app. If your ranges are pretty different from these, adjust your diet to see if changing them better supports your training.

Achieving Balance

It seems simple—if you’re burning all those calories during your workouts, the pounds should be melting away, right? Unfortunately, many triathletes find the scale moving in the opposite direction. One of the most common reasons is an increased appetite. 

Have you ever felt ravenous a few hours after a long run? Does your inner cookie monster make an appearance after your brick workout? If so, you’re probably familiar with this phenomenon.

Interestingly, most scientific research suggests that individual exercise bouts actually suppress hunger hormones rather than increase them. However, it’s unclear how this impacts endurance athletes who consistently train day after day. Anecdotally, training hunger is a real concern among many athletes.

On the flip side, some athletes fear weight gain and perpetually under-fuel themselves. At a minimum, this can cause poor training adaptations. At worst, it can be dangerous for your health.

Even more concerning, athletes who consistently under-fuel are at risk for a condition known as RED-S (relative energy deficiency in sport). This mismatch between dietary intake and energy expended can cause complications like menstrual dysfunction, poor immune health, weakened bones, loss of muscle mass, and other problems.

There’s definitely a careful balance here between supporting your training and supporting a healthy weight. However, it's achievable through a triathlete diet filled with lots of fruits, vegetables, whole grains, lean proteins, and healthy fats. 

Sample Daily Diet Plan

Curious what all of this looks like in an actual day's meals? Here’s an example of a balanced eating plan for a triathlete.

Breakfast

• Blueberry Oatmeal
  2 cups dry oatmeal cooked with 2 cups of milk
• 1 cup blueberries
• 1 teaspoon cinnamon
• 1/4 cup slivered almonds

Snack

• 1 cup low-fat cottage cheese
• 1 sliced peach
• 10 whole wheat crackers

Lunch

• Roasted veggie and turkey pita
  • 1 large whole wheat pita
  • 1 cup roasted red peppers
  • 1 cup sautéed or roasted zucchini (in ½ tablespoon olive oil)
  • 1/4 cup mozzarella cheese
  • 2 ounces turkey breast
• 1 medium-sized baked sweet potato
• 2 small fig cookies

Snack

• Apple with 3 tablespoons peanut butter

Training Session

• Sports drink (16 ounces)

Dinner

• Pasta with veggies and meat sauce
  • 1 1/2 cups cooked whole grain spaghetti
  • 1 tbsp olive oil
  • 1 cup zucchini
  • 1 cup cherry tomatoes
  • 1 cup marinara sauce
  • 5 ounces 90/10 (ratio of meat to fat) ground beef

Snack

• 30–40 grams of casein supplement shake

Keep in mind that your specific calorie needs will vary based on your height, weight, gender, training regimen, and metabolism. For competitive athletes with intense training regimens and for long course athletes, carbohydrate and calorie needs would increase.

The Keto Diet

Many athletes follow, or are curious about, the ketogenic diet. While this diet may help some athletes lose body fat and reduce reliance on carbohydrate for fuel, it’s not the magical panacea that many make it out to be.

Nutrients

The ketogenic diet flips traditional athlete macronutrient ratios. Those on the keto diet eat very few carbohydrates, moderate protein, and high amounts of fat. The goal is to shift your body from using carbohydrates for fuel to using fat for fuel.

In theory, this sounds ideal. Your body has far more fat available for energy production, and if you can train it to use more of that fat, all the better for performance, right?

Research

Unfortunately, while the first part is true—you do shift towards using more fat for fuel —research has not shown improved performance. One study found that a 10-week ketogenic diet helped athletes lose weight and body fat, and they were able to better utilize fat as a fuel source. 

However, there was a statistically significant decrease of 2 minutes in time to exhaustion. Other performance measures trended towards a negative effect as well, and athletes reported an inability to easily undertake high-intensity sprints.

Another study on elite race walkers found that while a ketogenic diet increased fat oxidation, it also decreased exercise economy. In other words, it became harder for athletes to perform at race-level intensity. There was also no improvement in athletes’ performance during an intensive three-week training protocol, while other diet interventions (high-carb and periodized diets) led to quicker times.

Among average healthy adults (not competitive athletes), research has shown that a ketogenic diet led to similar performance reductions. For example, a study in the journal Nutrition & Metabolism demonstrated a reduction in VO2 (amount of oxygen measured in the body during intense exercise) peak and peak power.

So is a ketogenic diet worth exploring? That’s a personal decision only you can make. While it may lead to weight loss and better body composition, it’s also possible that it could negatively impact performance. Keep in mind that no matter what style of eating plan you follow, you want it to be something you can stick with for the long term.

Pre-Workout Nutrition

If you’ve nailed down your daily diet, now it’s time to get into training and race day nutrition, starting with your pre-exercise meal. Eating before a long workout not only satisfies your stomach and prevents hunger, but it also tops off your energy stores. Try eating a pre-workout meal that fits the following criteria:

• High in easily digestible carbohydrates. For most athletes (with the possible exception of fat-adapted keto athletes), eating a high-carb meal prior to exercise improves performance.
• Moderate in protein. You'll eat more protein post-workout for recovery.
• Low in fat and fiber. Both can lead to gastrointestinal upset if eaten too close to your workout.
• Timing: Have your pre-workout snack at least 60 minutes prior to your workout to prevent the risk of a low sugar crash.

Sample Pre-Workout Meals

These options meet the high-carb, moderate protein, low-fat, low-fiber criteria:

• Toaster waffles topped with fruit and maple syrup or honey
• Bagel with cream cheese or peanut butter
• Fruit smoothie
• Skillet sweet potatoes and scrambled eggs
• Pasta with red sauce
• Chicken and rice
• Quinoa with poached eggs

Some researchers believe that a meal with low glycemic index carbohydrates—carbs that raise the blood sugar level more slowly—is optimal. However, review studies on this topic are inconclusive. It appears the most important aspect of the pre-exercise meal is simply to include carbs, not necessarily the types of carbs you choose. Also, do not make drastic changes from how you eat and train to when you eat on event day.

You do want to consider selecting carbohydrates that match your own digestive tolerance, though. For example, many individuals are sensitive to the effects of fiber during exercise—the last thing you want is a mid-race rush to the porta-potty. It's wise for many triathletes to avoid high-fiber fruits, vegetables, or whole grains prior to a big training session or race.

Meal Timing

In between your training sessions, you want to make sure you have adequate fueling, not just before your intense workout. Twenty four to 48 hours before your mock-event day and event day, you may need to start fueling up. Eating too close to your session can cause gastrointestinal upset, while eating too far out can leave you lacking energy. 

Of course, one to four hours before exercise is still a fairly large time range. How do you know what is best for you? Practicing is the best way to find out.

Generally, the farther out from your training session, the bigger the meal you’ll need to start out feeling fueled. This scenario also provides more flexibility for a wider variety of food, since you’ll have more time to digest.

Eating about an hour before your long run? A bagel with a little cream cheese might be a perfect option for you. Eating four hours beforehand? You might have a bigger meal, like a breakfast hash and a fruit smoothie.

Fueling During Exercise

During exercise, your nutrition concerns should focus on carbohydrates, hydration, and electrolytes.

Hydration and Electrolytes

For exercise lasting less than an hour, drinking plain water works just fine. If you’re exercising for over 60 to 90 minutes (or it is very hot outside), you’ll want to take in carbohydrates, fluid, and electrolytes—specifically sodium. Though several electrolytes are lost in sweat, including magnesium, sodium is lost in the largest amounts.

The rate at which you sweat and the sodium that is lost varies from athlete to athlete. Research has shown that high sodium losses in sweat can lead to slightly lower blood sodium levels. This, combined with fluid overload, may increase the risk of hyponatremia—a dangerous drop in blood sodium levels.

Rest assured, though, that it’s easy to meet your sodium needs during exercise. Instead of drinking water for long sessions, you can drink a commercial sports drink. You can also use fizzy electrolyte tabs that you add to water. Or, you can drink water and use a salt replacement product designed for athletes.

Fuel Types and Timing

If you’re training for longer than 60-90 minutes, you’ll also want to add some carbohydrate-based fuel during exercise. Your muscles are working hard, and keeping a steady stream of carbs flowing gives them the energy to continue to do so.

Aim for 30 to 60 grams of carbohydrate for every hour of exercise. Start fueling every 15 minutes with a 6-8% carbohydrates solution. You will be consuming about 6 to 12 ounces of fluid ounces per hour. Even though your body doesn’t necessarily need fuel yet, it’s helpful to get a steady stream of carbohydrates flowing to get your digestive system used to processing the fuel and to prolong the amount of time before you hit the wall.

Fuel can come in many sources, but they should be rich in easily digestible carbohydrates. You can choose options specifically manufactured for sport, or you can choose grocery store options that will also meet your needs. For example:

• Sports drinks
• Gels
• Shot blocks
• Gummies
• Raisins
• Bananas
• Fig bars

What this looks like in practice: Say you’re going on a 3-hour bike ride. You might decide to consume a gel (15 grams of carbohydrate each) every 15 minutes of your training ride, or 1/3 cup of raisins (38 grams of carbohydrates) every hour. Either of these options would fuel you at that rate of 30 to 60 grams per hour.

The only exception to this advice is for fat-adapted ketogenic athletes. If you’ve chosen to follow that type of diet, you probably won’t need to eat at these rates since your body can utilize more fat as fuel. 

Post-Workout Nutrition

Proper recovery nutrition is a key part of the triathlete diet. You’ll replenish energy stores in your muscles and start the muscle fiber repair process, both of which will help you arrive at your next session in optimal condition.

Keep in mind that not every workout needs a large recovery meal. Sometimes recreational athletes make the mistake of eating big recovery meals after every workout, which can contribute to excess calories and weight gain. Instead, focus on recovery meals and snacks after:

• Long, moderate intensity workouts that last more than two hours
• High-intensity workouts that last more than an hour
• The first workout, if you are doing two-a-day workouts and are a competitive athlete

Recovery Nutrients

In those three situations, take in carbohydrates along with some protein within 30 to 60 minutes of completing your workout. You can wait up to two hours for maximum results, but it's ideal to consume carbohydrates and protein ASAP after you finish your workout. Just how much carbohydrate depends on your body weight.

For example, let’s say you weigh 72 kilograms (160 pounds). Using the calculation above, that would mean you’d aim for 86 grams of carbohydrate after your workout. This may seem like a lot, but it can easily be built into a filling post-workout meal. Along with that carbohydrate, most people should include 15 to 25 grams of protein.

Masters-age athletes may experience slower recovery rates compared to younger athletes, possibly due to issues with protein remodeling in the muscles after exercise. Because of this, some researchers have suggested that older athletes take in a bit more protein after exercise (perhaps around 25 to 30 grams).

Remember, for shorter sessions you don't have to worry about these amounts. You can maximize recovery after short workouts with a small carbohydrate and protein snack—for example, a glass of chocolate milk or Greek yogurt with fruit. 

A Word From Verywell

There’s no one-size-fits-all triathlon diet that fitd every single person. Your training schedule, body type, genetic makeup, and food preferences are unique to you. Following the basic tenets of healthy eating for athletes, though—like consuming lots of nutrient-dense whole foods and focusing on good pre-exercise and recovery meals—will have you crossing the finish line like a champ.