Dr. Emily Kraus, Sports Medicine Physician and Director of the FASTR (Female Athlete Science and Translational Research) program at Stanford University, joins us to dig into one of the most overlooked areas of women’s health: bone density, bone stress injuries, and the hidden epidemic of Relative Energy Deficiency in Sport (RED-S). Dr. Kraus breaks down exactly why female athletes are at disproportionately high risk for bone stress injuries and how under-fueling, even when unintentional, can trigger hormonal suppression, menstrual cycle dysfunction, and long-term skeletal consequences.
The conversation spans everything from iron deficiency and foot strike hemolysis to the surprising relationship between estrogen, strength training, and bone building across the lifespan. If you think bone health is only a concern after menopause, this episode will completely reframe how you think about your body at every age.
What we explore:
What RED-S is and why it affects far more women than anyone is diagnosing
Why female athletes are at higher risk for stress fractures than male athletes
The silent signs of under-fueling that appear long before you lose your period
Fasted training and young female athletes: why skipping breakfast is not neutral
Iron deficiency in active women: how to test it, which form to take, and why runners are especially vulnerable
Jumping vs. running for bone health, and how to ease into plyometrics safely
How perimenopause accelerates bone loss and what you can actually do about it
Why hormonal contraception can mask RED-S and complicate the clinical picture
Estrogen and bone health: the case for transdermal estrogen in certain athletes
Strength training for bone density: why muscle quality matters just as much as bone density scores
Wearables and the future of early detection for overtrained, under-fueled athletes
Why sleep is a non-negotiable part of bone recovery for athletes at every age
About Dr. Emily Kraus:
Dr. Emily Kraus is a sports medicine physician and researcher at Stanford University, where she directs the FASTER Program: Female Athlete Science and Translational Research. Her work is focused on closing the gender gap in sport science by producing rigorous research and translating it into real-world clinical tools. She splits her time between treating athletes and leading research on bone health, energy availability, and the female hormone system across the athletic lifespan. She’s one of the clearest, most practically minded voices working at the intersection of performance and women’s health.
Connect with Dr. Emily Kraus:
Website: https://fastr.stanford.edu/ (Including practical nutrition and fueling infographics built specifically for female athletes.)
Instagram: https://www.instagram.com/stanfordfastr/ | https://www.instagram.com/emilykrausmd/
For a deeper look at the research coming out of FASTR over the past few years: https://drive.google.com/file/d/1QYW2ekv6JGMo4MhoKwnp4SZhg5NtDSIk/view?usp=drive_link
Timestamps
00:00 Intro: Why Women Lose Bone Density Faster Than You Think
03:46 What Is RED-S and Why Most Doctors Miss It
06:01 5 Warning Signs You May Have RED-S Right Now
08:21 Why Fasted Training and Carb Fear Are Wrecking Your Health
11:17 How to Test and Treat Iron Deficiency in Female Athletes
15:12 Why Runners Lose Iron Faster Than Any Other Athlete
17:16 How to Rebuild Bone Density During Perimenopause
20:43 Stop Eating for Leanness Eat for Longevity Instead
25:27 How Birth Control Masks RED-S Symptoms in Athletes
29:54 Estrogen Protects Your Bones: What to Ask Your Doctor
34:38 How Strength Training Builds Bone Density at Any Age
39:03 Why You Cannot Catch Up on Sleep and What to Do Instead
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