Fat Fuelled Ironman: From Energy Gels to Chief Bars

Fat Fuelled Ironman: From Energy Gels to Chief Bars

Updated: Mar 26, 2024Veronika Larisova

John Hill is Sydney’s triathlon icon and coach for many athletes from elites to weekend warriors. He has completed over 100 Ironman races - most less than 10 hours! That’s including 25 Hawaii Ironman world championships!

If you are not aware, full distance Ironman racing consists of 3.86km swim, 180.25km cycle and 42.2km run. John is a multiple Australian Champion and World Sprint Triathlon Champion 2009. He's has been ranked world number one in his age category in both full and half Ironman triathlons to name a few of his countless athletic achievements. Today, John is 62, still racing and moving like 20-something years old. He hasn’t been injured over the past 30 years!

Getting off the sugar gels

John used to be known as the "Gels King" as he used to consume energy gels during all his training sessions and races. He’s been training 30+ hours every week most of his life and admitting to having gels every 20-30min during his training sessions.

We caught up with John to talk about his latest decision to switch from traditional carbohydrate fuelling to predominantly fat fuelling, which is a huge adjustment for someone like him. This is what we discovered…

John used to fuel with gels for decades with great results but one day the same gels started to make him feel seriously ill. He’d suffer nausea and vomiting every single time he ate any conventional gels. Hence he went to a doctor two weeks before one of his numerous races, despite feeling fit and strong, and his GP convinced him to get a heart scan done.

Two weeks later, about to start his race, John received a call from his doctor ordering him to take himself to the hospital immediately because he was about to have a heart attack according to the scans. John went from the race straight to surgery. His artery was 90% blocked and he needed a stent. The years of a diet high in sugar made John’s blood vessels chronically inflamed which in the end lead to blockages, according to a renowned cardiac specialist. That was a big wake up call for John. Not wanting to take medication as that would affect his athletic performance, John decided to gradually switch to a ketogenic-type diet based on fresh whole foods and high fat and low carb gels and bars (such as Chief bars) for training and racing. Furthermore, he started to run all long slow training runs fasted and only eat before and during high-intensity sessions. John hasn’t drunk any alcohol for over a decade due to being aware that alcohol is highly inflammatory and that it lowers testosterone, robs the body of vitamins and minerals and hinders post-training recovery.

Ever since ditching gels and other sugary endurance products, John’s dizzy spells and vomiting during Ironman racing and training completely vanished. He does not take any blood-thinning medication and his heart is perfectly fine.

Focus on recovery

Besides training more than 30 hours each week (a combination of running, cycling and swimming), John spends lots of time on his recovery. He incorporates easy weeks but never takes a week off. He races in Europe during the Australian winter, which means he does not have off-season as a majority of triathletes do. He also works at his store, Fast Gear, in the Sydney CBD.

With all triathlon races getting cancelled this year, John has not had the chance to test the fat fuelling in practice. However, he has been experimenting in his training sessions as well as in unofficial races within his team. Surprisingly, his performance seems to be as good as when fuelling on carbs… minus nausea. For the time being, this confirms the science research findings, which we summarised in one of our previous blog posts. John says he performs well no matter what fuel he chooses for his endurance regime. Most importantly, he cares more about his health now and this is why he is sticking to fat fuelling in the future. 

More Triathletes Ditching the Sugar

An increasing number of John’s competitive athletes are also drifting away from using traditional high-sugar gels. Simply to prevent stomach upset, which has a positive impact on their race times as they are not slowed down by cramps and vomiting. Moreover, by ditching the energy gels, the athletes will automatically lower the risk for inflammatory injuries. 

We can’t wait for the triathlon events to resume next year to see John smashing it fuelled on Chief bars.

John’s current weekly triathlon training volume 

  • Bike 20 hrs (6 hrs max ride )
  • Run 10-12 hrs (4-5 hrs max run)
  • Swim 3-4 x 30 min (because it’s winter and no races)
  • Daily stretching and foam rolling

Nutrition over the past three months 


3 eggs, avocado, bacon, tomatoes, MCT oil, cheese, almonds

Lunch options

Dinner leftovers

Chief Bars (collagen and meat)

Homemade keto protein ball


Chicken, fish, kangaroo or beef with vegetables (especially beetroot), almond butter, MCT oil, almonds or cashews

95% dark chocolate for a treat

Sipping on 

electrolytes with MCT oil throughout the day



Veronika Larisova 

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