Fuel your
training.
Nutrition is triathlon's fourth discipline — and what you eat affects how you train, recover and feel on race day.
Nutrition is often called triathlon's fourth discipline — and for good reason. What you eat shapes how you train, how you recover, and ultimately how you feel on race day.
This isn't a race-day nutrition plan. You'll find that in our Race Prep guide. This is the everyday foundation underneath it: eating well enough to support your training and recover properly between sessions.
The Basics: Carbs, Protein, Fat
Three macronutrients do most of the work.
Carbohydrates
Carbohydrates are your primary fuel source, particularly for anything longer or harder than an easy session. They're stored in your muscles and liver as glycogen — essentially your body's readily available energy reserve.
Whole grains, oats, rice, potatoes and fruit are all reliable carbohydrate sources.
Protein
Protein supports muscle repair and recovery. Training places stress on muscle tissue; protein provides the building blocks needed to repair and maintain it.
Eggs, tofu, legumes, Greek yoghurt, dairy and lean meats are common protein sources. Spreading protein across several meals and snacks is generally more useful than consuming most of it in one sitting.
Healthy Fats
Dietary fat supports health and provides a concentrated source of energy, particularly useful when overall energy requirements are high.
Avocados, nuts, seeds, olive oil and oily fish are useful sources, alongside the wider nutritional benefits they provide.
Some useful starting points
Endurance athletes often work within broad ranges such as:
- Carbohydrates: roughly 5–7g per kg of bodyweight on regular training days, with higher intakes sometimes appropriate during particularly demanding training periods.
- Protein: roughly 1.2–2.0g per kg of bodyweight per day.
- Fat: commonly around 20–35% of total daily energy intake.
These are general endurance-sport ranges, not personal prescriptions. Your ideal intake depends on factors including training volume, body size, goals and overall health.
Eating Around Training
What you eat before and after training can make a noticeable difference to how you feel during a session and how well you recover afterward.
- Carbohydrates before exercise can provide readily available energy for the session ahead.
- Eating carbohydrates after harder or longer sessions helps replenish glycogen stores.
- For longer sessions, particularly those lasting more than about 60–90 minutes, practising fuelling during exercise becomes increasingly important.
- Gels, chews, sports drinks and simple foods such as bananas can all be useful depending on the session.
- Before a long or hard session, a carbohydrate-focused meal can help ensure you're not starting the session under-fuelled.
- Rest days don't need to look exactly like training days. Your overall intake should reflect the amount of work you're doing, while protein and a balanced diet continue to support recovery.
Hydration — The Other Half of the Equation
Hydration matters just as much as food when you're training regularly. Fluid requirements vary considerably with body size, temperature, exercise duration and sweat rate.
- A general starting point for daily fluid intake is around 30–35ml per kg of bodyweight, with additional fluid often needed in hot conditions or during heavier training.
- Sodium and other electrolytes become increasingly relevant as exercise duration, heat and sweat losses increase.
- Don't rely on thirst alone during long sessions. Practising your hydration strategy in training is particularly important before race day.
- Urine colour can provide a simple indication of hydration status, although it isn't a perfect measurement.
A Few Principles Worth Keeping in Mind
Consistency beats perfection.
Getting your nutrition broadly right most days will take you further than an occasional "perfect" day surrounded by inconsistency.
Real food works.
You don't need specialised sports products for most everyday training. Bananas, oats, rice, potatoes, nuts, yoghurt and homemade snacks can fuel plenty of sessions effectively.
Sports products absolutely have their place — particularly during longer sessions and racing — but they aren't a requirement for every workout.
Plan ahead.
Meal preparation and having reliable food available makes consistent, balanced eating much easier around a busy training schedule than deciding what to eat at the last minute.
Nutrition Is Individual
There is no single perfect triathlon diet. Nutrition needs vary with body size, training load, goals, food preferences, sport background and individual health circumstances.
The information here is general guidance rather than individual medical or nutritional advice. If you have specific health conditions, dietary restrictions or performance goals, a registered dietitian or sports nutritionist can help you build a plan around your individual needs.