Ironman blog by Jenny – follow me on my journey to Ironman Austria (My first & only full distance triathlon)

Where I plan to provide some insights, tips and thoughts that any outdoor endurance sport enthusiast might find interesting, regardless of your level, sport or distance.

2 – March ’25 – Nutrition

3 months into my ironman training block, back from a successful training camp in Lanzarote, and as my weekly training hours are approaching the 12 hour mark, it is time to discuss “the 4th discipline”. Nutrition.

Endurance athletes often get bogged down in their swim, bike and run etc data, continuing to progress the duration and intensity as they progress toward their A-race, but without the correct nutrition (this of course goes for any endurance sport), then you are simply not going to achieve what you need from your training. Your body needs fuel to perform and recover.  Afterall, you wouldn’t put petrol in a diesel car and expect it to work well.

“You wouldn’t put petrol in a diesel car and expect it to work well.”

Nutrition that is correct for your body, and your needs, plays a crucial role when training for an endurance sport.

Get in wrong, and your performance, recovery, and overall well-being will be impacted. Unfortunately you can’t just assume that because peanut butter sandwiches work for your ultra-marathon running buddy, that they are going to be a good idea for you. There is certainly a trial and error component.

In short… fuelling your body with the right nutrients ensures that you can train harder, perform better, and recover faster! But why…

1. Energy Supply: Endurance sports require prolonged energy output. Your body primarily uses carbohydrates and fats for fuel. A well-balanced diet helps ensure you have enough glycogen (stored carbohydrates) and fat reserves to sustain your efforts during long workouts or races.

2. Muscle Recovery: After long training sessions (the same can also be said for muscular injury recovery), your muscles need to repair and rebuild. Protein is vital for muscle recovery, and consuming it after a workout helps speed up the process, reducing soreness and helping you get back to training sooner.

3. Hydration and Electrolytes: When you sweat, you lose both water and electrolytes (sodium, potassium, magnesium). Proper hydration and electrolyte balance are key to maintaining muscle function, avoiding cramping, and sustaining performance during long efforts. When taking on hydration, be sure to add electrolytes to your water to replenish those lost minerals. Want to find out what electrolyte levels might be best suited for you – visit https://www.precisionhydration.com/ These guys are some in the best in the world in this area!

4. Preventing Fatigue: Depletion of energy stores, especially carbohydrates, leads to fatigue, decreased performance, and even hitting the “wall” during a race. Nutritional strategies, like carb-loading before an event, help to maximise energy stores and delay the onset of fatigue. Prolonged exposure to excessive fatigue can also leave you more vulnerable to injury and illness.

5. Immune Function: Talking of illness…Intense training can temporarily suppress the immune system, making athletes more susceptible to illness. A nutrient-dense diet with adequate vitamins and minerals (such as vitamin C, zinc, and antioxidants) can help support immune health and reduce the risk of sickness. No one ever wants to get ill, but having to take a week out of training due to illness, or worse, missing the event you have been building toward for months due to illness is the last thing you want.

6. Mental Focus: Nutrition also impacts cognitive function. Carbs are not only vital for physical energy but also for brain function. Maintaining stable blood sugar levels through a balanced diet helps with mental clarity, focus, and decision-making during long events.

7. Adaptation to Training: Proper nutrition aids in maximising the training adaptations, such as increased aerobic capacity, better endurance, and stronger muscles. It also helps prevent overtraining and burnout by supporting your body’s repair and recovery processes.

Fuelling aspects I have learnt (sometimes the hard way!)

  • Practice is key – nothing new on race day

This sounds obvious but as with successfully completing a block of training, consistency is key. You need to know what foods work (and maybe more importantly don’t work!) for you. For me, bread is an absolute no, where-as a handful of salted crisps on a long run are a winner.

  • What are you aiming for? Chances are, you are not a pro

High level professionals and teams will work with nutrition therapists to optimise their fuelling, but in reality for the rest of us, this isn’t the case. Getting some advice that you can implement into your training, while trying to juggle family / work / general life, will stand you in good stead. Try to avoid mindless eating – everything you put in has a consequence.

  • Time before session

For me, my fuelling timings vary depending on what activity I am doing. An low intensity 4 hour bike ride…porridge and sliced banana an hour before. Going for a run…I need at least 1.5hours after a light meal, ideally more like 2hours.

  • Does it need to be “fancy sports nutrition”

In short – no. For example, a packet of wine gums have around 76g carbs in a 190g bag and come in at price point significantly less than a top sports brand. Can’t stand energy gels? Don’t worry. While it is worth trying a few brands to see which textures and makeup works for you, some people just don’t  like using gels, and that’s fine.  Adding some kitchen salt to your water bottle can be a simple way of reducing cramp risk. On the flip side however, practicing with a nutrition brand that you know will be provided at your chosen event ensures you are confident your body responds well.

In summary…

Practice. You are an individual, not a car. So trial fuelling combinations in your training sessions and keep a note of what worked and what didn’t. It can absolutely make or break your race day.