Jelle Geens
Precision Fuel & Hydration IRONMAN 70.3® World Championship
Nice3rd, MPROJelle's headline numbers
Jelle's strategy
Fueling
T - 1-4hrs: Ate a carb rich meal (Low in fat & fibre)
T - 15mins: Took in a final dose of carb
"I’d got through one carb bottle by the top of the climb and a few sips into my second. By that point I was too cooked to put my elastic band around the bottle, and it bounced straight out over the next speed hump. After that, I was just trying to salvage my plan."
Jelle’s race morning followed a well-practiced routine starting with a breakfast of cooked white rice with honey, banana, 500ml of PH 1500 (Tablets), and then one PF 30 Caffeine Gel in the final 15 minutes before the start. After an excellent swim, Jelle got to work on the bike as part of a huge group of 27 athletes who came out of T1 together. The bike plan was built around two bottles each containing a prototype carbohydrate drink mix plus one PF 30 Caffeine Gel, providing a total of 135g of carbs per bottle. This is a well-tolerated dose for Jelle and in line with the gut training he has put in over recent seasons. He was still on plan by the top of the Col de Vence, having consumed one of his carb bottles, but losing his second bottle after only having a few sips significantly impacted his overall carb intake for the bike leg.
He tried to adapt well in the moment, picking up a couple of on-course gels at the fourth aid station, meaning he was able to partially offset the loss, which kept his intake at a still-strong ~92g/h. On the run he had his final PF 30 Caffeine Gel in the first kilometre, then a further two PF 30 Gels to fuel the effort. He had planned to take a fourth gel, but reported some slight gut discomfort early on, which was enough that he chose not to risk further stress on the gut - a sensible call given how much a fast pace mattered to his overall placing.
Set against his title-winning Marbella performance in 2025, where he averaged ~98g/h, this was a step back purely in the numbers, but the context matters. His underlying strategy and tolerance for a high carbohydrate rate are clearly still there.
Hydration
Taking on board an appropriate amount of fluid and sodium is essential to maintaining blood volume and supporting the cardiovascular effort needed to perform on race day.
Whilst the absolute amount of sodium and fluid consumed per hour is important, it’s critical to consider these in relation to each other. This is known as 'relative sodium concentration' and it’s expressed in milligrams per litre (mg/L). How much sodium you’re taking in per litre of fluid is more important than the absolute amount taken in per hour.
Jelle612mg/L
Jelle has been Sweat Tested to dial in his hydration plan
Sweat sodium concentration (mg/L) is largely genetically determined and remains relatively stable. Knowing how salty your sweat is enables you to replace a good proportion of your sweat losses, which can range from 200-2,000mg/L.
Whilst Jelle's losses are on the low side, getting his hydration strategy right is still crucial when it's hot and/or humid as his higher sweat rate in these conditions can result in significant net losses over the duration of a race.
Learn moreT - 60mins: Drank ~500ml of strong electrolyte drink
"We were going too fast at the 3rd aid station on the bike to get water, so I had to wait until 75km to pick up more. The gels I had to pick up after losing one of my carbs bottles also didn’t have sodium, so I wondered if I might be a little low going into the run."
As always, Jelle ensured he started the race hydrated by consuming 500ml of PH 1500 (Tablets) on race morning. This turned out to be more important than ever, given that he lost one of his concentrated carb and sodium bottles on the descent of the Col de Vence, and therefore was left no option but to pick up additional fluid to consume from the 4th aid station on the bike.
Thankfully, Jelle’s bottles on the bike include a higher relative sodium concentration than his losses and therefore losing one of two bottles did not impact his relative sodium concentration during this part of the race. This meant that he wasn’t in a significant sodium deficit by the time he hit the run, and could take his usual approach of using plain water from the aid stations to stay on top of his hydration.
Caffeine
Beyond the Three Levers of Performance (carb, sodium and fluid), caffeine is one of only a few substances that is proven to improve performance for most endurance athletes as it can help stave off mental and physical fatigue.
T - 0-4hrs: Had a final hit of caffeine
Following a successful trial at IRONMAN 70.3® Zell am See a couple of weeks prior, Jelle upped his caffeine intake for this race. He took in ~5.1mg/kg of caffeine, comfortably towards the top of the 3-6mg/kg range typically associated with a performance benefit. His caffeine came from three PF 30 Caffeine Gels, spaced throughout the day: one in the final half hour before the swim, one on the bike, and one within the first kilometre of the run. This was a marked improvement in execution on 2025, when a dropped gel in T2 at Marbella left him under-dosed at ~100mg (~1.6mg/kg), short of the effective range. This time, the staggered three-gel approach delivered a meaningful, well-timed dose across the full distance and is a strategy worth repeating.
How Jelle hit his numbers
Here's everything that Jelle ate and drank on the day...
Final thoughts
“It’s been a rollercoaster of a season, so I’ve got to be proud of the race I had.”
“A third place ended Jelle’s bid to become the first man to win three straight IRONMAN 70.3® World Championship titles, but given a season disrupted by injury and a much-reduced race calendar, a World Championship podium is a strong marker of where his form has returned to. He dealt well with the adversity of losing a bottle on the bike and managed to re-group to run one of the fastest run splits of the day. We’re looking forward to supporting Jelle as he prepares to step up to the full IRONMAN® distance.”
PF&HJelle's full stats
Data Confidence
We rate each of our case studies from 1-5 based on the level of accuracy, and our confidence in the data.
There is good confidence in the accuracy of the data reported. An athlete feels that the numbers closely reflect what they consumed despite a couple of estimations which may carry some degree of error. The majority of what was consumed is recorded to a high level of specificity (most volumes are known through the use of bottles brands quantities flavours). The numbers are very plausible and align with previous data recordings (if an athlete has collected data previously).