Research · 3 min read · 2026-10-12
Eating enough to train
Eating too little for the training you do can affect health and running, in both women and men. The warning signs to take seriously.
Running burns a lot of energy. When you eat too little compared with how much you train, it can affect both your health and your running. The International Olympic Committee updated its expert statement on this in 2023.
What the experts describe
The condition is called relative energy deficiency in sport, or REDs. It occurs when energy intake is too low for the training you do, so the body has too little left for its normal functions. It affects both women and men.
Since the previous statement in 2018, more than 170 new studies have been published. The new statement points to a growing role of too little carbohydrate, to a link with mental health, and to more evidence about the effects in men. It also introduces a new clinical tool to help doctors detect and diagnose REDs.
What it means for you
Eat enough to support the training you do, especially in periods with more or harder training. Carbohydrate is an important part of that for runners.
Warning signs that are worth taking seriously include missed or irregular periods, stress fractures, frequent illness, and fatigue or poor performance that doesn't improve with rest. If you recognise this, talk to a doctor. It can be treated, and it is better to act early.
What the statement can't tell you
The statement is aimed at doctors and sports organisations. It can't tell you how much you need to eat, and REDs is diagnosed by a doctor, not from a list of signs.
How we use it
PX7 Training doesn't give diet plans or weight goals. If training keeps feeling harder than it should, say so when the app asks how you feel, and talk to a doctor about it.
Source
- Mountjoy et al. (2023), 2023 International Olympic Committee's (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs). British Journal of Sports Medicine.
Written by Jørgen Larsen for PX7 Training.