Why Women Gain Weight on the Same Diet as Men: Fueling, Fasting, and Biology with Dr. Stacy Sims

**Mary Claire Haver** (0:00)
Because there was so much to cover with Dr. Stacy Sims, we have broken this episode into two parts. This is part one, and we will publish part two later this week.
You've not touched once on calories in calories out in our entire conversation so far. And for so many of our listeners, that is all they've been told. That was all I was taught in medical school.

**Stacy Sims** (0:21)
Yeah, that's what we were taught earlier too. But when you start looking at that, the human body is not an algorithm, and we see the brain uses more fuel than some of the adipose tissue. And if we start thinking about calories in, calories out, it doesn't quite work. Because calories is also a rough idea of how much energy a food has.
And it also comes down to quality, because we're now in ultra-processed, global ultra-processed food. And people are like, oh, I had 2,000 calories. And if you look at the 2,000 calories of someone, I hate to say this, but I'm going to in the US diet is the typical American diet.

**Mary Claire Haver** (1:00)
Yeah. Standard American diet.

**Stacy Sims** (1:02)
It's different from other countries who don't have access to all the ultra-processed foods. So that's where I'm like, I don't want to talk about calories in, calories out. I want to talk about the timing of your food, the quality of your food, and a focus on protein and fiber for your gut microbiome. And we need protein for satiation, not just lean mass development.

**Mary Claire Haver** (1:30)
The views and opinions expressed on unPAUSED are those of the talent and guests alone, and are provided for informational and entertainment purposes only. No part of this podcast or any related materials are intended to be a substitute for professional medical advice, diagnosis or treatment.
Today's guest wrote a book that made me go back and look at advice I've been giving for years and realize some of it was wrong. I found her the way I find most people who end up changing how I practice medicine. I saw a video of hers, I looked her up, and two hours later, I was still reading about Dr. Stacy Sims. Then I read her book, Next Level, and I started rethinking things, not just for my patients, but for myself, the way I was training, the way I was eating around training, the way I had been telling women in my clinic to push through, eat less, do more cardio, and wondering why their bodies were not cooperating. I was giving advice, built on research that was never designed with women's bodies and mind. Not bad advice by the standards I was trained to believe, just incomplete. And incomplete in perimenopause and menopause is costly. Dr. Stacy Sims is an exercise physiologist and nutrition scientist who has spent her career studying how women's bodies actually work across the menstrual cycle, across perimenopause and menopause, and across every stage of athletic performance. She has worked with elite Olympic athletes and everyday women trying to figure out why their bodies stopped responding. She has taught and coached at Stanford, authored two influential books, Roar and Next Level, that have reshaped the conversation around women and exercise. A few years later, I was invited to the Diary of a CEO roundtable on women's health.
Seven hours, some of the sharpest people in this field, and I spent half of it watching Dr. Stacy Sims be more certain, more precise, and more right than I had even expected. That doesn't happen often.
Women are not small men. That's not a rallying cry. That is a biological fact with specific clinical consequences that we are only now beginning to properly address. This episode is going to inform how you move, how you eat, and how you think about what your body actually needs, not what works for everyone, what works for you. I'm Dr. Mary Claire Haver, a board certified obstetrician and gynecologist and certified menopause practitioner. I'm also an adjunct professor of obstetrics and gynecology at the University of Texas Medical Branch. Welcome to unPAUSED, the podcast where we cut through the silence and talk about what it really takes for women to thrive in the second half of life.
Dr. Stacy Sims, welcome to unPAUSED.

**Stacy Sims** (4:27)
Thanks for having me. I'm so happy to be here.

**Mary Claire Haver** (4:29)
You are one of the most requested guests. So we are so, so, so excited to have you here. So you are a former professional athlete.

**Stacy Sims** (4:40)
Bike racing, yes.

**Mary Claire Haver** (4:42)
And you've worked with Olympians, but you've also worked with like normal people like me. So most of our listeners are just mere mortals and humans.