As a nutritionist, I often hear a familiar story: "I'm training more, but I feel constantly drained, I’ve stopped progressing, and I keep getting injured! What am I doing wrong?"

If this resonates with you, you could be under-fuelling.

Our bodies are incredible, adaptable machines, built for survival. Yet, the modern drive to "push harder" and "eat less" can inadvertently conflict with our fundamental biology. Under-fuelling occurs when your calorie intake isn't sufficient to cover your body's essential functions, daily activities, and the demands of your physical training. When your fuel tank consistently runs low, your body shifts into survival mode, slowing down your metabolism and prioritising survival over performance.

This can show up as persistent fatigue, a decline in performance, constant illness, and recurrent injuries. But the good news is that these are simply your body’s signals asking for help.

In this post, we’ll dive into the hidden costs of under-fuelling and, more importantly, the actionable steps you can take to hit the reset button, restore your health, and finally start thriving.