Twenty seven female triathletes at the 2024 IRONMAN World Championships completed questionnaires, kept 48 hour food diaries, and sat for semi structured interviews before and after the race. Dietary analysis was possible for 23 of them.
Only 6 of 23 (26%) reached the 8 to 12 g/kg carbohydrate loading guideline. Mean intake was 6.4 ± 2.1 g/kg. Higher carbohydrate intake correlated with faster finish times (r=-0.50, p=0.035). Fibre intake correlated strongly with GI symptom severity (r=0.85, p<0.001).
The interviews found the shortfall was not a knowledge gap. The barriers named were perceived behavioural control, travel logistics, emotional regulation, and athlete identity around eating.
The numbers
| Met the 8 to 12 g/kg carb loading guideline | 6 of 23 (26%) |
| Mean carbohydrate intake | 6.4 ± 2.1 g/kg |
| Carbohydrate intake vs finish time | r=-0.50, p=0.035 |
| Fibre intake vs GI symptom severity | r=0.85, p<0.001 |
What this does not show
- That carbohydrate caused the faster finishes. The r=-0.50 association is a correlation. Faster athletes may simply tolerate more carbohydrate rather than carbohydrate making them faster.
- That fiber causes GI distress in general. The r=0.85 correlation covers fibre eaten in the 48 hours before an IRONMAN. It says nothing about habitual fiber intake outside race week.
- That the numbers are definitive. The quantitative arm is n=23 at a single event. The findings are directional, not definitive.
- That education fixes execution. These athletes largely knew the targets. The study identifies practical and emotional barriers, but it did not test any intervention against them.
Caveats worth holding
- Correlational throughout; causation cannot be inferred in either direction.
- n=23 for the quantitative arm, at a single championship event.
- The fibre and GI symptom finding is specific to the 48 hours before an IRONMAN and should not be read as a general statement about fiber.
- Content built on this study should avoid pressure framing around eating.
- Summarized from the abstract; the digest advises verifying against the full text before citing any claim.