Relative Energy Deficiency in Sport: Signs, Risks & Recovery | Pragmatic Nutrition

Most athletes I work with aren't undereating on purpose. They're training six days a week, eating "clean," and still watching their times plateau, their periods disappear, or their fractures pile up. Almost every time, the missing piece isn't more discipline; it's more food.

This is Relative Energy Deficiency in Sport, or RED-S, and it's one of the most under-diagnosed performance issues I see in Indian athletes, especially teenagers.

What Is Relative Energy Deficiency?

Relative energy deficiency occurs when an athlete's energy intake doesn't cover both their training demands and the basic functions their body needs to function. This includes hormone production, bone building, immune defence, digestion, and growth (1, 2, 3).

An athlete's body has to fund two competing demands: the energy cost of training and the energy required to maintain normal physiology. When food intake consistently fails to cover both, the body adapts. This is low energy availability; the central concept underlying Relative Energy Deficiency in Sport (RED-S). The response is not simply “the body shutting down.”

Instead, energy allocation and physiological signalling change, and over time this can impair reproductive function, bone health, endocrine and metabolic function, immune function, gastrointestinal function, cardiovascular health and psychological wellbeing. Importantly, RED-S does not look the same in every athlete; the effects depend on the magnitude and duration of low energy availability, training demands and individual factors.

The term replaced the older "Female Athlete Triad" (low energy availability, menstrual dysfunction, low bone density) because we now know this affects male athletes, teenagers, and non-endurance sports just as often. It's simply missed more often in these groups because nobody's looking for it.

What is the Cause of REDs?

This is the point I push back on hardest with parents and coaches: RED-S doesn't require restrictive intent. In my practice, most cases come from:

• Increase in training volume: Not fueling as per training volume and continuing to eat less. This is common in teens who suddenly move from club to state or national-level training.

• "Clean eating" culture: Cutting rice, roti, or ghee because it's seen as unnecessary, when these are exactly what refill glycogen and calorie needs after long sessions.

• Weight-sensitive sports: gymnastics, distance running, swimming, combat sports, and aesthetic sports, where leanness is (wrongly) equated with performance.

• Poor appetite regulation after intense training: some athletes don't feel hungry enough post-session to eat what they actually burned.

None of this looks like disordered eating from the outside. That's exactly why it goes unnoticed until performance or health markers break down.

Warning Signs Parents, Coaches and Athletes Miss

RED-S rarely announces itself with one dramatic symptom. It shows up as a cluster:

• Performance plateaus or unexplained regression despite consistent training

• Frequent colds, infections, or slow recovery from minor injuries

• Stress fractures or bone injuries with no obvious trauma

• Irregular or absent periods in female athletes (never "normal" for a trained athlete, regardless of what's commonly assumed)

• Digestive symptoms such as bloating, constipation, or reflux that worsen with training load

• Poor concentration, irritability, or disrupted sleep

• In teens: growth or height gain slowing down against their expected trajectory

If you're already following our guide on sports nutrition for teenage athletes. RED is essentially what happens when the fuelling gaps described there are left unaddressed for months.

Why Indian Athletes Are Particularly Vulnerable

A few patterns I see repeatedly in Indian sporting households:

1. Carbohydrate fear. Rice and roti often get cut first when a family "tightens up" a young athlete's diet, right when carbohydrate needs are highest.

   
   

2. Protein overcorrection. Supplement-heavy approaches (as we've discussed in our guide to whey protein). Sometimes these supplements replace real meals, leaving total energy intake short even when protein looks adequate.

   
   

3. Exam season collisions. Training load stays high while meal structure falls apart during academic stress, a uniquely common Indian pattern in teen athletes.

   
   

4. Under-fueled gut symptoms mistaken for "sensitivity." Bloating, acidity and irregular digestion under high training load often get treated as food intolerance, when they're actually a downstream sign of low energy availability.

This is one of the reasons I look at gut health and sports performance together rather than as separate problems.

How I Assess REDs Risk

There's no single blood test that confirms REDs. It's a clinical picture built from training load, food intake, menstrual/hormonal history, injury history, and symptoms over time. In consultations, I typically look at:

• A detailed food and training log (not just "what did you eat," but when, relative to sessions)

• Menstrual history for female athletes, growth trajectory for teens

• Injury and illness frequency over the past 6–12 months

• Energy, mood, sleep, and digestive symptom patterns

• Where relevant, coordination with a sports physician for bone density or bloodwork

  
  

Recovery: What Actually Works

The fix is rarely "eat a little more." It usually needs a structured, monitored increase in energy availability, done without triggering fear of weight gain or performance dips in the short term:

• Rebuild total energy first, before fine-tuning macros; most athletes need more total food before they need "better" food.

• Anchor carbohydrates at every meal, not just around training. This is the single most common gap I correct.

• Protect recovery meals within 30–60 minutes post-session. Timing matters as much as quantity.

• Reintroduce feared foods deliberately: rice, ghee, and full-fat dairy are performance foods, not indulgences.

• Track trends, not days. Athletes and parents often want quick fixes; RED-S recovery is measured in weeks to months, with regular reviews.

This is also where supplements get misused. Creatine, protein powders, or BCAAs (see our blogs on the creatine loading phase and BCAA risks) are sometimes added on top of an energy deficit, hoping they'll compensate. They can't. Supplements sit on top of adequate fuelling; they don't substitute for it.

My Stand

RED-s isn't a niche endurance-athlete problem, and it isn't caused by "not trying hard enough" to eat well. It's usually the predictable result of training demands outpacing food strategy, often while everyone involved believes the athlete is eating "healthy." Treating symptoms individually (a supplement for fatigue, a gut plan for bloating, iron tablets for low energy) without correcting overall energy availability rarely works. The food has to come first.

If your athlete is training hard and something isn't adding up in performance, periods, recovery, or growth, it's worth a closer look before it becomes a bone injury or a burnout story.

Book a Free Discovery Call with Meenu to get a personalised assessment, or explore our Sports Nutrition Program built specifically for competitive and recreational athletes in India.

Meenu Balaji is a clinical gut health and sports nutrition specialist and founder of Pragmatic Nutrition, with 14+ years of global experience across the UK, New Zealand, and India. She works with competitive teen and adult athletes across India on performance nutrition, recovery, and long-term health.

Reference:

Consensus statement 2023 International Olympic Committee’s (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs)-https://bjsm.bmj.com/content/57/17/1073