The Unseen Adversary: How Nutritional Deficiency Sidelined Elite Triathlete Lionel Sanders

The Mysterious Condition That Halted a Champion

Imagine being at the peak of your athletic career, racking up victories and eyeing your next big challenge, only to be stopped dead in your tracks by an invisible force. This is exactly what happened to Lionel Sanders, a top-tier Canadian triathlete, whose season was abruptly interrupted not by an injury you can see or easily diagnose, but by something far more elusive and potentially devastating: Relative Energy Deficiency in Sport (RED-S).

Sanders, fresh from triumphs at Oceanside and St. George 70.3, was gearing up for a promising 2025 IRONMAN season when he suddenly found himself grappling with severe mobility issues after a routine training session. The pain was intense and unexplainable, as he noted, "I couldn't walk normally, couldn't go downstairs, couldn't lift anything."

This began a journey of medical mysteries and consultations, leading to the discovery of RED-S, a condition that arises from chronic under-fueling relative to the energy expended during training. This revelation not only put his immediate competition plans on hold but also opened up a broader discussion about the nutritional demands of elite endurance athletes.

Timeline of a Triathlete's Trial

During a routine 20K run: Sanders felt great, with no signs of trouble.
By evening: Minor discomfort appeared, dismissed as insignificant.
The next morning: A bike session went well, but discomfort lingered.
By the next run: The pain worsened slightly.
Hours later: Sanders was in severe pain, unable to bear weight on his foot.

Despite extensive medical imaging, no structural damage was found, deepening the mystery and frustration. This lack of visible injury is a hallmark of RED-S, where the damage is metabolic and systemic, rather than muscular or skeletal.

Decoding RED-S: More Than Just a Calorie Deficit

RED-S is about more than just feeling hungry; it's a serious syndrome that affects multiple body systems, disrupting everything from bone health to hormonal balance and mental well-being. Sanders' realization that he had been consistently under-eating—missing his caloric needs by about 1,200 to 1,500 calories daily—highlighted a critical gap in his training regimen.

This condition is particularly prevalent in endurance sports, where the culture often glorifies leanness and high training volumes can mask the signs of under-fueling. The consequences are severe, potentially derailing careers and compromising long-term health.

Beyond the Physical: The Psychological Strain of Invisible Injuries

One of the toughest aspects of dealing with RED-S is its invisibility. Athletes like Sanders face not only the physical repercussions but also significant psychological stress. The uncertainty of an undiagnosed condition, the frustration of unexplained performance dips, and the forced inactivity can take a heavy mental toll.

A New Race Strategy: Nutritional Overhaul and Managed Expectations

Sanders' response to his diagnosis has been proactive and positive. He's adjusted his race calendar, increased his caloric intake significantly, and set his sights on a strong return, viewing this setback as an educational opportunity that might ultimately enhance his performance.

"I think we may have just found a way to gain an extra two, three, four percent in performance," Sanders speculated, hopeful about the potential benefits of addressing his nutritional needs more accurately.

Lessons for Every Athlete: Recognizing and Preventing RED-S

Sanders' experience serves as a powerful reminder for all athletes about the importance of adequate nutrition. It's not just about fueling for today's workout but supporting your body's overall demands and recovery needs. Here are signs that you might be under-fueling:

Persistent fatigue or decline in performance
Slow recovery and frequent injuries
Mood swings and sleep disturbances
In women, changes in menstrual cycles

Conclusion: A Call to Action for Nutritional Awareness

Lionel Sanders' journey through the challenges of RED-S underscores a critical aspect of athletic performance that often goes overlooked: nutrition. As Sanders prepares for his upcoming races with a renewed focus on fueling his body correctly, his story is a stark reminder to all endurance athletes of the need to match their nutritional intake with their physical output.

This isn't just about avoiding injury; it's about unlocking potential, achieving personal bests, and sustaining a long and healthy athletic career. Whether you're a weekend warrior or a world-class competitor, take a moment to assess if you're truly giving your body what it needs to perform at its best.