Exercise & Nutrition Scientist: The Truth About Exercise On Your Period! Take These 4 Supplements!

Exercise & Nutrition Scientist: The Truth About Exercise On Your Period! Take These 4 Supplements!

The Diary of a CEOJan 6, 20252h 4m

Dr Stacy Sims (guest), Steven Bartlett (host), Narrator, Narrator

Systemic male bias in sports science and medical researchSex differences in physiology: muscle, heart, lungs, fat distribution, Q‑angleMenstrual cycle phases and cycle‑aware training and nutritionFasting, calorie restriction, and weight loss differences between men and womenInjury risk in women (especially ACL) and strength training for preventionPerimenopause, menopause, and menopause hormone therapySupplements and recovery tools: creatine, vitamin D, Omega‑3, iron, saunas, cold plunges

In this episode of The Diary of a CEO, featuring Dr Stacy Sims and Steven Bartlett, Exercise & Nutrition Scientist: The Truth About Exercise On Your Period! Take These 4 Supplements! explores women Aren’t Small Men: Rethinking Training, Fasting, Menopause, Supplements Dr. Stacy Sims explains how most exercise, nutrition, and sports science protocols are built on male data and why applying them directly to women often backfires. She details fundamental sex differences in physiology—from muscle fiber type, heart and lung size, to the menstrual cycle, perimenopause, and menopause—and how these change training, fasting, recovery, and injury risk.

Women Aren’t Small Men: Rethinking Training, Fasting, Menopause, Supplements

Dr. Stacy Sims explains how most exercise, nutrition, and sports science protocols are built on male data and why applying them directly to women often backfires. She details fundamental sex differences in physiology—from muscle fiber type, heart and lung size, to the menstrual cycle, perimenopause, and menopause—and how these change training, fasting, recovery, and injury risk.

Women’s brains are more sensitive to low energy intake, making popular strategies like fasted training, aggressive intermittent fasting, and keto particularly harmful to female muscle, hormones, and metabolism. Instead, she advocates cycle-aware fueling, heavier resistance training, high‑intensity work, and protein-forward nutrition across the lifespan.

Sims also breaks down ACL injury risk, bone health, sleep and jet lag differences, and how tools like creatine, vitamin D, Omega‑3, and menopause hormone therapy can support health when used correctly for women. The overarching message: women must train, eat, recover, and supplement in ways that match their unique biology, not male norms.

Key Takeaways

Most exercise and nutrition protocols are built on male data, so copying men’s strategies often harms women.

Sports science recruitment has historically prioritized 18–22-year-old men; women were excluded because menstrual cycles were deemed ‘too complex’. ...

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Women’s brains are more sensitive to low energy, making fasted training and aggressive fasting risky.

The female hypothalamus has more kisspeptin-sensitive regions that monitor nutrient availability. ...

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Training, fueling, and expectations should change across the menstrual cycle—not every day is equal.

In the low-hormone follicular phase (roughly days 1–13 if ovulating), women are more resilient to stress, handle carbs well, and tend to perform best physically and cognitively—this is a prime window for PRs, high‑intensity work, and heavy lifting. ...

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Strength training—especially for posterior chain and power—is non‑negotiable for women at every age.

Women are born with more endurance-oriented fibers and less upper‑body strength, have a wider Q‑angle, smaller hearts and lungs, and more quad dominance. ...

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Perimenopause is ‘reverse puberty’ that radically changes metabolism, fat storage, sleep, and mood—but it’s manageable.

From roughly 35 to early 50s, fluctuating estrogen and progesterone alter blood lipids, increase visceral (abdominal) fat via changes in liver fat handling, disrupt sleep, and blunt exercise adaptations. ...

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Popular ‘biohacks’ like cold plunges, keto, and warrior fasting work very differently in women than men.

Extreme cold plunges (0–4°C) are calibrated to male thermoregulation; in women they’re often too cold, trigger excessive vasoconstriction, and don’t produce the same parasympathetic, glucose, and mood benefits. ...

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A few targeted supplements are strongly evidence-based for women: creatine, vitamin D3, iron when needed, and sometimes Omega‑3.

Women store only ~70% of the creatine men do, and they use it for fast energy in gut, brain, and muscle. ...

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Notable Quotes

We’re looking at sports science research—from training to eating to recovery—it’s based on male data, and women have been generalized to that data.

Dr. Stacy Sims

If you’re a woman doing fasted training, all you’ve effectively done is burn through your lean mass.

Dr. Stacy Sims

Did science just look at women as a different version of men? A smaller version of men? For the most part, yes.

Dr. Stacy Sims

Exercise is a stronger stimulus for autophagy than fasting is… all the things we hear about fasting and longevity, exercise does the same—and better.

Dr. Stacy Sims

Perimenopause is reverse puberty. Every system in your body is being affected because your sex hormones are changing.

Dr. Stacy Sims

Questions Answered in This Episode

For a woman currently doing early-morning fasted training and intermittent fasting, what is the most evidence-based way to transition her routine without rapid weight regain or energy crashes?

Dr. ...

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How would you build a month-long training plan for a recreationally active woman that explicitly aligns workout types (HIIT, strength, recovery) with each phase of her menstrual cycle?

Women’s brains are more sensitive to low energy intake, making popular strategies like fasted training, aggressive intermittent fasting, and keto particularly harmful to female muscle, hormones, and metabolism. ...

Get the full analysis with uListen AI

Given the microbiome concerns you raised about ketogenic diets, what would a ‘gut-healthy’ version of low-carb eating look like for women who feel better with fewer carbs?

Sims also breaks down ACL injury risk, bone health, sleep and jet lag differences, and how tools like creatine, vitamin D, Omega‑3, and menopause hormone therapy can support health when used correctly for women. ...

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In perimenopause, how do you decide when lifestyle changes alone are sufficient and when it’s time to consider menopause hormone therapy, especially for women with family histories of hormone-sensitive cancers?

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What metrics beyond scale weight and cycle regularity should women track (e.g., ferritin, vitamin D, HRV, sleep stages) to catch early signs that their training or nutrition is no longer supporting their hormones and long-term health?

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Transcript Preview

Dr Stacy Sims

A lot of women come with their partners to see me and say, "I don't understand. We're both doing the same training. He's leaning up and getting fitter. I'm putting weight on and getting slower." And that is because we hit puberty. We have our reproductive years. We may not have pregnancy in there. We have perimenopause, we have postmenopause, we have menstrual cycle. Each one of those is a different hormone profile that can affect the way we eat and the way we train. But no one told us this or what we can do.

Steven Bartlett

Until right now. Dr. Staci Sims is an exercise physiologist and nutrition scientist.

Narrator

Whose best-selling books and over 100 peer-reviewed studies is revolutionizing how women can optimize their health, fitness, and longevity by working with their unique physiology.

Dr Stacy Sims

We're looking at sports science research, everything from training to eating, recovery. It's based on male data, and women have been generalized to that data. Things like we see men do really well on calorie restriction and fasting, but for women, it doesn't happen that way, and we'll talk about that. And we also know that during puberty, girls' hips widen, shoulders widen, which changes our angle of the knee to the hip, what we call the Q angle, so they don't feel comfortable running or swimming or jumping. And because they're not taught this stuff, we see that by the age of 14, girls who previously were sporty, over 60% of them drop out of sport. The problem is, it's never about how we can empower women to use their physiology to their advantage.

Steven Bartlett

So let's change that.

Dr Stacy Sims

Let's go.

Steven Bartlett

As it relates to nutrition and exercise, how do I need to adapt across the menstrual cycle? What's your view on cold plunges and supplements like creatine, and what's the variance between men and women as it relates to sleep? And then let's talk about menopause, starting with perimenopause.

Dr Stacy Sims

I'm excited.

Steven Bartlett

The Diary of a CEO is independently fact-checked. For any studies or science mentioned in this episode, please check the show notes. This has always blown my mind a little bit. 53% of you that listen to this show regularly haven't yet subscribed to this show. So could I ask you for a favor before we start? If you like this show and you like what we do here and you wanna support us, the free simple way that you can do just that is by hitting the subscribe button. And my commitment to you is if you do that, then I'll do everything in my power, me and my team, to make sure that this show is better for you every single week. We'll listen to your feedback. We'll find the guests that you want me to speak to, and we'll continue to do what we do. Thank you so much. (upbeat music) Dr. Staci Sims. What is the work that you do, and why is it so important that you do it?

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