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 triathlete diet can be the difference between your best time yet and an upsetting finish. Build your endurance nutrition IQ with the tips below and get ready for your best tri season yet.

While it’s tempting to jump right into race day nutrition, 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.

Luckily, a nutritious triathlete diet doesn’t vary much from standard healthy eating recommendations, but you should anticipate eating more during the on season and less during the off season to accommodate changes in energy output. 

You can break it down into three essential pillars:

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 for your body while molding your body and exercises to meet the needs for swimming, cycling, and running.

Of course, these concepts may sound easier in theory than in practice, but sticking with them will serve you well.

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. 

That said, most triathletes will fare well using these recommended ranges:

Aim for 45 to 65% of calories, approximately 3–12 grams of carbohydrates per kilogram of weight). Simple carbohydrates like bananas should be consumed at least 30 minutes prior to your workout. During intense exercise longer than an hour, try fast-absorbing carbohydrates like gels.

Aim for 10 to 30% of calories, or 0.8–1 grams per kilogram of weight on rest days to 1.7–2 grams when training more than four hours per day. Timing is important. Since your body can't store protein, it should be consumed throughout the day and best within two hours of post-workout.

Aim for 20 to 35% of calories. While fat is important for nerve function, organ protection, and is a source of fatty acids, if performance and achieving a new personal best time is vital, a high-fat diet can slow you down. We dig deeper into this below.

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 look out of whack, you can adjust your diet to see if these ranges better support your training.

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 want to 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 overall 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. 

Curious what all of this looks like in an actual day's meals? Here’s an example of what this might look like:

• Blueberry Oatmeal:
  • 1 cup dry oatmeal cooked with 1 cup of 1% milk and 1 cup water
  • 1 cup blueberries
  • 1 teaspoon cinnamon
  • 1/4 cup slivered almonds

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

• Roasted Veggie and Turkey Pita with a side of a sweet potato and fig cookies:
  • 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 baked sweet potato
  • 2 small fig cookies

• Apple with 1 tablespoon peanut butter

• Sports drink (16 ounces)

• 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

• 1 cup raspberries and 1 tablespoon dark chocolate chips

• 3,300 calories (28% fat, 53% carbohydrates, and 19% protein)

Keep in mind 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.

Many athletes are running (quite literally) to 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.

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?

Unfortunately, while the first part is true—you do shift towards using more fat for fuel —research has not shown improved performance. A study in The Journal of the International Society of Sports Nutrition 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 the athletes to perform at a certain race-level intensity. There was also no improvement in athletes’ 10-kilometer race walk 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 (non-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 life.

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
• low in fat and fiber—both can lead to gastrointestinal upset if eaten too close to your workout

Here are some meal ideas to consider that meet these 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—the carbs that raise the blood sugar level more slowly—is optimal. However, recent meta-analyses on this topic are inconclusive. It appears the most important aspect of the pre-exercise meal is simply to include carbs for performance, not necessarily the types of carbs you choose.

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 session or race.

Ideally, you’ll want to eat your pre-exercise meal about one to four hours before long or intense workouts. 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 arrive at the starting line 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.

During exercise, your nutrition concerns should focus on three things: hydration, electrolytes, and fuel.

For exercise lasting less than an hour, drinking plain water works just fine.

If you’re exercising for over an hour, you’ll want to take in both fluid and electrolytes—specifically sodium. Though several electrolytes are lost in sweat, 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.

If you’re training for longer than one hour and 15 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 around the 30 to 45-minute mark. Even though your body doesn’t necessarily need fuel yet at that point, 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. 

Here are a few examples:

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

Wondering what this looks like in practice? Let’s say you’re going out on a 3-hour bike ride to train this weekend. You might decide to consume a gel every 45 minutes of your ride (25 grams of carbohydrate each) or eat 1/3 cup of raisins every hour (38 grams of carbohydrates). 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. 

Proper post-workout nutrition is a key part of the triathlete diet, as it aids in recovery. 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, though. Sometimes recreational athletes make the mistake of eating big recovery meals after every workout, which can contribute to excess calories and weight gain.

Instead, remember these key times to focus on recovery meals and snacks:

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

For the rest of your short training sessions, your everyday diet will serve just fine as far as recovery. 

For the three situations mentioned above, you’ll want to be sure to 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 closest to the time you finish your workout.

Just how much carbohydrate depends on your body weight. If you want to dial down your nutrition plan with specific amounts, you can calculate it yourself.

For example, let’s say you’re a 72 kilogram (160 pound) athlete. Using the calculation above, that would mean you’d aim for 72 to 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 by scheduling a small carbohydrate and protein snack afterward–for example, a glass of chocolate milk or Greek yogurt with fruit. However, you don’t have to focus on the larger amounts of carbohydrates and protein in these situations.

There’s no one-size-fits-all triathlete diet that will fit every single person. You have a different training schedule, body type, genetic makeup, and food preferences compared to anyone else. Following the basic tenants of healthy eating for athletes, though—like chowing down on 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.