If you’re a driven, high-achieving female athlete, chances are you put everything else first before eating. Training, work, family, recovery, the next goal on the calendar — food quietly slides to the bottom of the list, not because anyone told you to skip it, but because there’s always something that feels more urgent in the moment.
Here’s the uncomfortable truth: underfueling isn’t a fringe issue affecting a small subset of “extreme” athletes. It’s the norm hiding in plain sight.
The numbers are staggering
Research on female endurance athletes paints a sobering picture. In one study of over 200 female endurance athletes, roughly 66% were found to be at risk of low energy availability — meaning their bodies simply weren’t getting enough fuel to support both their training load and basic physiological function. Close to 25% showed signs of exercise addiction, and about one in five reported disordered eating behaviors.
Sit with that for a second. This wasn’t a study of athletes with diagnosed eating disorders. These were everyday endurance athletes — the kind who show up to track workouts, log their long runs, and generally look like they’ve got it together. And still, low energy availability was the majority experience, not the exception.
Why “eating enough” is crucial for performance
Low energy availability, or Low EA, happens when the energy you take in from food isn’t enough to cover both your training demands and the energy your body needs to run its basic operations — hormone production, bone remodeling, immune function, and more. When there isn’t enough energy to go around, the body doesn’t sound an alarm right away. Instead, it quietly starts to ration.
This is the mechanism behind Relative Energy Deficiency in Sport, or RED-S — a syndrome that goes well beyond “the female athlete triad”. RED-S recognizes that underfueling doesn’t just threaten bone density and menstrual cycles; it can also compromise your metabolic rate, immune function, cardiovascular health, growth and development, and yes — the very performance gains that you are seeking.
That last point is the cruel irony. Many athletes restrict food because they believe it will make them leaner, faster, and more competitive. In reality, chronic underfueling tends to do the opposite: more injuries, more illness, stalled performance, and a hormonal cascade that can take months or years to fully unwind.
The hormone connection
When the body senses it isn’t getting enough energy, it starts deprioritizing “non-essential” functions — and reproductive hormone production is often first on the chopping block. This can show up as irregular or absent periods, which many athletes are told (incorrectly) is just a normal side effect of training hard. It isn’t. It’s a signal.
Left unaddressed, this hormonal disruption doesn’t stay contained to the menstrual cycle. It ripples outward — affecting bone density (increasing stress fracture risk), thyroid function, mood, sleep, and long-term cardiovascular health. The athletes who are “toughing it out” through missed periods and constant fatigue are often the same ones quietly setting themselves up for the injuries that end seasons.
A common misconception is that a regular period is proof everything is fine. It isn’t. You can have a regular cycle every month and still be in a meaningful energy deficit — the two aren’t mutually exclusive. A regular cycle is a reassuring sign, but it isn’t a clean bill of health on its own, and it can lull athletes (and even the clinicians treating them) into overlooking a deficit that’s still affecting bone density, recovery, and long-term performance in the background.
This is exactly why RED-S looks beyond menstrual status alone. Relying on “my period is normal” as the sole checkpoint can mean real energy deficits go undetected for months or years — quietly doing damage the whole time.
What makes this so hard to catch
Underfueling rarely looks like what people expect. Most athletes at risk are not underweight. Many are performing well — for a while. Because Low EA develops gradually and the body compensates for a surprisingly long time before symptoms become obvious, both athletes and the people coaching them can miss it entirely, right up until an injury, a diagnosis, or a plateau forces the conversation.
That’s part of why awareness matters so much here. If nearly two out of every three female endurance athletes are at risk, this isn’t a niche concern — it’s a conversation that belongs in every training plan, every coaching relationship, and every athlete’s own self-check-ins.
Moving from awareness to action
Recognizing the risk is the first step, but it’s not the finish line. Real change comes from:
- Reframing fueling as training — food isn’t separate from your training plan; it’s part of it.
- Tracking energy availability, not just calories — the goal isn’t more restriction, it’s matching intake to your actual training demands.
- Normalizing the conversation — talking openly about fueling, cycles, and recovery so athletes don’t feel like they’re failing when they need to eat more.
- Getting support early — a missed period, unexplained fatigue, or a stress reaction injury deserves a real look, not a shrug.
Underfueling isn’t a badge of discipline. It’s a treatable, preventable risk — and the athletes who fuel properly aren’t the ones falling behind. They’re the ones still standing at the finish line, season after season.
If you’re a female athlete wondering whether your training and fueling are actually working together — or working against each other — that’s exactly the conversation worth having.
