Triathlon Nutrition 101: Why Fueling Is the Fourth Discipline

In triathlon, nutrition is often called the fourth discipline — and for good reason. You can be fit, consistent, and prepared, but without proper fueling, performance and enjoyment suffer quickly.

This post is meant to cover nutrition basics with practical amounts to help you get started. I’m not a registered dietitian or nutrition professional — I’m an amateur triathlete sharing what I’ve learned through training, racing, and plenty of trial and error. Nutrition is individual, and these are starting points, not rigid rules.

Also remember that everyone is different, so working with a qualified sports nutritionist could be extremely helpful. For example, I have a sensitive stomach and have found to prefer liquid nutrition during my races, and was able to get some great personalized recommendations from a nutritionist.

Why Nutrition Matters

Fueling affects:

• Energy and endurance

• Mental focus

• Muscle function

• Recovery and injury risk

Poor nutrition usually doesn’t show up right away — it shows up late in workouts or races, when fatigue stacks and decisions matter most.

Daily Nutrition: Supporting Training

Triathletes need enough energy to support frequent training sessions.

General daily priorities:

• Carbohydrates: Primary fuel source

• Protein: Muscle repair and recovery

• Fats: Overall health and hormone support

A simple framework:

• Eat regular meals and snacks

• Include carbohydrates at most meals

• Include protein consistently throughout the day

Underfueling during the week often leads to flat workouts and poor recovery — even if race-day nutrition looks “right.”

Pre-Workout & Pre-Race Fueling

The goal before training or racing is to start fueled, not full.

General guidelines:

• 1–4 g of carbohydrates per kg of body weight in the 1–4 hours before a key workout or race

• Lower fiber and fat closer to start time

Simple examples:

• Toast + banana + peanut butter

• Oatmeal with fruit

• Bagel with honey

• Rice with eggs

Practice this in training — race day is not the time to try something new.

Fueling During Training & Racing

For sessions or races lasting longer than ~75–90 minutes, fueling during exercise becomes important.

Carbohydrate intake:

• 30–60 grams of carbohydrates per hour for most Olympic-distance and training sessions

• 60–90 grams per hour for longer races (70.3+) if trained and tolerated

Fuel sources can include:

• Sports drinks

• Gels

• Chews

• Easily digestible solids

Personal faves: Tailwind Hydration Mix, Maurten Gels

Consistency matters more than perfection — start fueling early and stay steady.

Hydration & Electrolytes

Hydration needs vary widely based on weather, sweat rate, and individual tolerance.

General starting points:

• 16–28 oz (500–800 ml) of fluid per hour

• 300–700 mg of sodium per hour, depending on sweat rate and conditions

Personal faves: Propel Electrolyte Mix, Sport Beans

Hot or humid races may require more fluids and electrolytes, while cooler conditions may require less.

Post-Workout Recovery Nutrition

Recovery starts immediately after training.

Aim for:

• Carbohydrates: ~1–1.2 g per kg of body weight within the first hour

• Protein: ~20–30 g shortly after training

• Fluids to replace sweat losses

This doesn’t need to be fancy — a balanced meal or snack works just fine.

Practice Nutrition Like You Practice Training

Fueling should be trained, not guessed.

Use workouts to:

• Practice timing and amounts

• Test different products

• Learn what your stomach tolerates

• Build confidence in your plan

The more familiar your fueling strategy is, the calmer race day becomes.

Keep It Simple

It’s easy to get overwhelmed by numbers, trends, and social media advice. Most athletes perform better with simple, consistent fueling than with overly complex strategies.

Start with:

• Adequate calories

• Regular carbohydrates

• Practiced race nutrition

Adjust gradually and intentionally.

Final Disclaimer

I’m still learning — and nutrition is highly individual. These guidelines reflect commonly used ranges and personal experience, not medical or professional advice. If you have specific health needs or performance goals, working with a qualified sports nutrition professional can be incredibly helpful.

Fueling well isn’t just about racing faster — it’s about staying healthy, consistent, and enjoying the sport long-term.