‘I was poisoning myself before endurance events’

Indoor bike workouts of five to six hours. Thirty hours a week of training.

One of the “craziest” training regimes an athlete can have is one that needs proper fuelling.

But, in trying to carb-load to perform at the highest level, Britain’s four-time world champion across a range of Ironman and triathlon disciplines says she was “actually poisoning” her body in the process.

For years, Lucy Charles-Barclay had been dealing with stress fractures, joint pain and low energy – with no explanation for the symptoms.

But that all changed in 2024 when she received a “game-changing diagnosis” of coeliac disease, an autoimmune condition whereby consuming gluten causes the body’s immune system to attack internal organs, including the small intestine.

In short, the pasta she had been eating to boost her energy for competition was in fact damaging her body.

Fuelling is critical for any endurance event. Triathletes are often racing for more than four hours, in hot and humid conditions.

The one-day Ironman 70.3 endurance event – also known as a Half Ironman – starts with a 1.2-mile swim, before 56 miles on the bike, and finishes with a 13.1-mile half-marathon.

Charles-Barclay won her second world Ironman 70.3 title last month, in Marbella.

“This year, my season opened in Singapore which is one of the most brutal conditions to race in,” Charles-Barclay told BBC Sport. “Even for the swim the water is hot, so you’re basically swimming in a bath before getting out for the biking and running.”

That’s just the race.

“I’m usually training for about 30 hours,” the 32-year-old added. “I’m doing strength and conditioning, mainly to prevent injury. It’s really intense on the body.”

Carbohydrates – the body’s primary energy source during endurance activities – are key to race preparation, during the race, and recovery.

When you think of carbohydrate-rich foods, bread, pasta, and cereals might all come to mind.

But for people with coeliac disease, a lot of these go-to carbohydrate sources are off-limits, because they contain gluten.

In the two years before her diagnosis, Charles-Barclay had broken a foot during a race, experienced two stress fractures and two calf muscle tears.

It was a gruelling sequence of “just getting another injury, then recovering, then getting another injury”.

“And we couldn’t work out what was happening,” she said.

“As you can imagine, consuming gluten for 30 years without knowing you are a coeliac will do quite a bit of damage.”

For all those years, her body was less able to absorb nutrients from the food she consumed, leading to those multiple injuries.

“Getting the coeliac diagnosis was a real lightbulb moment,” she said.

“I think for a lot of people it’s quite upsetting to find out. But for me, it was such a positive change.”

Charles-Barclay said her diet is “not the easiest thing to manage”, particularly when so many staple carbohydrates had to be immediately cut out and substituted. Gluten is also hidden in products where you might not expect it, like condiments and even sports supplements.

Charles-Barclay said it took about a year for her small intestine to heal after making the necessary changes to her diet.

She is now fuelled by entirely gluten-free options.

“Three days out from racing I will start to carb-load with multiple bowls of rice, chicken and boiled eggs a day,” she said.

“During the race, I use gluten-free gels. I aim to consume up to 120 grams of carbohydrates per hour during an Ironman.

“I add additional electrolytes from salt tablets to my water bottles and I get my extra energy during racing and training from Red Bull.”

She is in contention to win the T100 Triathlon World Championship at the final race of the season in Qatar on Friday, 12 December.

Going into that race, Charles-Barclay, Canada’s Julie Derron and fellow Briton Katie Waugh sit within nine points of each other on the leaderboard. Charles-Barclay is third in the standings, seeking a big final performance.

“It’s going to be hot, it’s going to be tough, but it’s going to be a really exciting race,” she said.

But at least now she knows how she needs to fuel, even if she has to take a mind-over-matter approach to some aspects.

“I have to eat rice multiple times a day for like three or four days going into the race,” she said.