Stacy Sims has one sentence that should be on the wall of every gym that still copies men’s programs onto women’s calendars: women are not small men. Exercise physiologist, nutrition scientist, former bike racer and Ironman athlete. PhD from Otago. Research time at Stanford, AUT, Waikato. The books are ROAR and Next Level. The TEDx talk is the short version of the career.
The practical load is about the cycle, peri-menopause, and the fact that fasting-plus-HIIT-plus-low-calories is a great way to flatten a female athlete. She wants more fuel around training, more strength work as estrogen drops, heat and hydration treated as physiology, not as toughness theater. If Huberman’s morning light is sex-agnostic, Sims is the reminder that a luteal-phase long run and a 50-year-old’s recovery are not the same protocol with the calories scaled down.
Osmo Nutrition was her product translation of earlier hydration research. She still teaches through her own site. The science of sex differences in sport is better than it was in 2006 and still thinner than it should be. That gap is why she exists on a biohacking site that otherwise talks as if everyone had the same androgen profile.
She is blunt, which reads as dogma if you wanted to keep doing 16:8 because a man on a podcast felt great. If you have a cycle, or you are in the decade where the cycle is leaving, read her before you copy Attia’s fasting chapter or a 20-year-old’s cut. Then lift. She will not be mad about the lifting.