Relative Energy Deficiency in Sport (RED-S) isn't only a women's issue. When training outpaces calories and recovery, men can develop low energy availability (LEA) — with stress fractures, illness, and hormonal suppression even though there's no period to track.
Unexplained fatigue, frequent colds, plateau or drop in performance, recurring bone pain, low libido, or irritability — often alongside eating less to 'lean out' for racing.
Signs to watch for
- ·Stress fractures or shin pain that keeps returning at similar mileage
- ·Low morning energy despite sleeping 7–8 hours
- ·Loss of sex drive or erectile changes during heavy training blocks
- ·Mood swings, anxiety, or feeling flat between runs
- ·Getting sick every time you add a hard week
- ·Dizziness or lightheadedness on easy runs
I thought I was just getting old at 28. Turns out I was under-fueling by about 800 calories a day. Once I ate like an athlete, my shin pain cleared and my easy pace dropped 30 seconds.
How to avoid
- ·Cutting calories aggressively while mileage climbs — 'race weight' goals often backfire
- ·Skipping post-run meals because you're 'not hungry yet'
- ·Assuming fatigue is weakness — RED-S in men is under-diagnosed because there's no obvious cycle signal
- ·Stacking two hard weeks without a recovery week
How to fix / recover
- ·Eat enough on rest days — repair happens when you're not running
- ·Add a recovery week (30–40% less volume) every 3–4 weeks when building mileage
- ·See a sports medicine doctor if bone pain, libido changes, and fatigue cluster together
- ·A sports dietitian can quantify energy needs if you're unsure you're eating enough
Practical fueling for men
- ·Many active men need 2,400–3,200+ kcal/day depending on size and training — under-eating by 500 kcal daily adds up fast
- ·Pre-run (60–90 min): toast with peanut butter, banana, or a small bowl of oatmeal
- ·Post-run (within 1–2 hours): protein + carbs — eggs on toast, chicken and rice, or a recovery shake
- ·Don't rely on coffee to replace breakfast before morning runs
Bone health without estrogen cues
- ·Men don't lose periods as a warning sign — stress fractures may be the first red flag
- ·Vitamin D, calcium, and adequate protein support bone remodeling during high-mileage blocks
- ·Strength training 2× per week loads bone in ways running alone doesn't
When to see a specialist
- ·Recurring stress fractures or bone pain that worsens with impact
- ·Cluster of fatigue, low libido, and performance drop — ask about RED-S / LEA workup
- ·History of disordered eating or compulsive weight cutting for racing
Related: Men's running guide · Nutrition basics
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