Are you Overtraining or Under-Fuelling?

Triathlon Nutrition Academy · Aug 13, 2026 · 26m

Your legs are heavy, your easy sessions feel hard, and you are not improving despite training consistently. If you immediately thought overtraining, you are right. That is also the exact symptom list for under-fuelling.

Researchers went looking for every training overload study that also measured what athletes were eating. 21 studies made the cut, and in 18 of them, 86%, the athletes were under-fuelled. So the majority of athletes diagnosed as overtrained in the research were in fact not eating enough. Which raises a fairly uncomfortable question about that extra session you are thinking of…