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

Dr. Mary Claire Haver, MD

26,219 views

In this episode of unPAUSED, Dr. Mary Claire Haver sits down with exercise physiologist and nutrition scientist Dr. Stacy Sims to unpack why so much fitness and diet advice built on male physiology leaves women confused about why the scale will not move, and why weight loss can feel so much harder for women than for men on the exact same plan. Dr. Sims, author of Roar and Next Level, a former professional cyclist who has taught and coached at Stanford, breaks down why women following the same diet and training program as their male partners often end up tired and stuck rather than leaner and fitter.

The conversation covers the biological reasons women conserve fat in a calorie deficit, how female circadian rhythm differs from male circadian rhythm, and why eating within an hour of waking helps regulate cortisol and appetite hormones like ghrelin and peptide YY. Dr. Sims explains why fasted workouts can backfire for women, why front loading calories earlier in the day supports better metabolic outcomes, and why time restricted eating works with a woman's biology in ways that intermittent fasting often does not.

Guest links:
Dr. Stacy Sims https://www.drstacysims.com/
Dr. Stacy Sims (Facebook) Facebook: drstacysims
Dr. Stacy Sims (YouTube) @drstacysims
Dr. Stacy Sims (Instagram) Instagram: drstacysims
Stacy T. Sims, PhD (LinkedIn) LinkedIn: stacy-t-sims-phd
Dr. Stacy Sims Newsletter https://www.drstacysims.com/generic_o...
Dr. Stacy Sims Microlearning Course https://www.drstacysims.com/microlear...

Books:
“Next Level: Your Guide to Kicking Ass, Feeling Great, and Crushing Goals Through Menopause and Beyond,” by Dr. Stacy Sims https://www.amazon.com/Next-Level-Kic...
“ROAR: How to Match Your Food and Fitness to Your Unique Female Physiology for Optimum Performance, Great Health, and a Strong, Lean Body for Life,” by Dr. Stacy Sims https://www.amazon.com/ROAR-Fitness-P...
“The New Perimenopause,” by Dr. Mary Claire Haver https://www.amazon.com/New-Menopause-...
“The New Menopause,"⁠ by Dr. Mary Claire Haver https://www.amazon.com/New-Menopause-...

For full show notes, please visit: https://bit.ly/unPAUSEDDrStacySims

00:00:00 – Why Calories Don't Tell the Whole Story
00:01:54 – Meet Dr. Stacy Sims
00:05:00 – Women Are Not Small Men
00:11:48 – Why Women Struggle to Lose Weight
00:17:17 – The Truth About Circadian Rhythm
00:27:17 – Should Women Exercise Fasted?
00:31:58 – How to Build Muscle After 40
00:38:04 – The Best Workout for Menopause
00:44:15 – Intermittent Fasting vs. Time-Restricted Eating
00:49:48 – Dr. Stacy Sims' Daily Nutrition Routine
00:53:53 – Why Exercise Beats Dieting
01:04:07 – Train for Healthspan, Not Weight Loss

Never miss an episode—sign up for The ’Pause Life Newsletter: https://thepauselife.com/pages/newsle...

Medical Disclaimer: The information, including opinions and recommendations, on this platform is meant for informational and educational purposes only. Mary Claire Media, LLC, the unPAUSED podcast, and The ’Pause Life are not medical organizations. Medical advice or medical diagnosis cannot be provided to you through the platform, any associated website, or customer portals. Using this platform does not establish a patient-physician relationship.

20 Comments

@drmaryclaire Creator 2 months ago Pinned

Thank you Dr. Sims, your insights will be more valuable than you realize! What was your favorite part of the conversation? Let me know in the comments below! xoxo, Mary Claire

@vanessamanchester3042 2 months ago

I love hearing all the conversations, but this honestly doesn't apply to many people, like nurses, flight attendants, restaurant workers, and others who have work schedules that are completely different from the typical 9-to-5. I still haven't heard a doctor or anyone else talk about how to truly thrive in a reality that doesn't fit the standard schedule. It often feels like the advice assumes everyone has the same daily routine, when that's simply not the case for millions of people working shifts, nights, weekends, or rotating schedules.

So, for those reading this, please take a moment to appreciate these workers and show them a little more compassion. They help keep our communities running, often while sacrificing routines, holidays, weekends, and sleep in ways many people never have to think about.

@melaniefox-smith8776 2 months ago

I particularly love Dr. Sims because she is a vegan athlete who knows how to achieve these goals without eating animals. No shade to the meat eaters, just nice to have an all inclusive conversation about how these goals can practically be supported on a plant based diet. Thank you!

@petrawagner4946 2 months ago

This is literally me. I've been getting so depressed for years. But sleep and food intake/appetite/timing problems began while in the military for 10 years. I couldn't eat at 4am. Still can't eat breakfast 20 years post- military. Never hungry, either but i try to get at lest my protein in. Protein coffee is my breakfast. Collagen protein. Food? Maybe by 12 or 1. Short on fiber, i know, but terrible gut issues since Badic Training.
This was an invaluable conversation.

@kellymark1679 2 months ago

Love the interview and info, but really struggle with all the ads!

@theveggiemistress7566 2 months ago (edited)

I drink a little protein drink made of vanilla or chocolate whey protein powder, 8 oz soy milk, 1 tbsp ground flaxseed, and few dashes of cinnamon upon starting the day

@andrearoper7641 2 weeks ago

This great conversation could be more helpful if you included whole food, plant-based options whenever food examples are given. This is my ask for better content. Those protein powders, many yogurts, etc. are ultra-processed foods too, imo.

@ericabestul1274 2 months ago

I love learning from this channel, but the amount and length of ads is sooooo much.

@lisabarrettwilson34 2 months ago

I heard Dr Sims talk about women needing to eat before working out. That was last year. I have since started doing that and I feel so much better during my workouts. All these years I was doing it all wrong thanks to bro science.

@maureenlandry3243 2 months ago

10 years ago I went to a female obgyn and her comment was, "I don't know what to do with you girls". I'd been fighting for care for 26 years at that point and just wanted to see if things had changed. They hadn't. Still haven't and I'm 77. You new warriors have a long road ahead but you are Hope fo next gen. I've been exercising my whole life. Consistency is the key not heroics. Just got back from 2 weeks of solo lake kayaking. It's about quality of life. Thanks for all you do. 🇨🇦

@AndrewD271 2 months ago

One of the biggest mindset shifts I've had recently came from reading Forbidden Body Secrets by Claire Valen. I always assumed body transformation was mostly about discipline, but the discussions around hormones, appetite, metabolism, and timing made me realize how much is happening beneath the surface. Whether you agree with every point or not, it completely changed the way I think about health.

@GenXfrom75 2 months ago (edited)

I’m being honest here- I’m in better shape today at 51 than I was in my 20s. I’ve lived a keto lifestyle for nearly 2 years now and it’s been the second best decision for my health… the first being HRT started 6 months ago.

@Laura_Ferreira_Ctba 2 months ago

Love Dra Stacy. Would you consider hyrox a good strength exercise?

@christinasouza2468 2 months ago

Dr. Mary Claire Haver and Dr. Stacy Sims, thank you both for the incredible work you’re doing for women. I just listened to your podcast together, and it really resonated with me.

I’m lucky enough to be on vacation this week, and something struck me at the hotel gym. Other than my daughter, my son, and me, every single person lifting weights was a woman over 40. 💪It made me smile because I truly believe that’s happening because of the message you’re spreading. You’re helping women understand that strength training is one of the best gifts we can give ourselves as we age.

I am so grateful I found your work in my mid 40s. You’ve completely changed the way I think about exercise, menopause, and caring for my body. Thank you for giving so many of us the knowledge and confidence to pick up the weights and invest in our future. You are making a real difference. 🌻💕💪

@Helliahanagy 2 months ago

So grateful to Stacy Sims for giving me the information I needed to be fitter and healthier than I’ve ever been in my life at an age my younger self was terrified to imagine

@dotty1212-o1t 2 weeks ago (edited)

This is opposite of what i have been learning as far as eating goes. Most menopause specialists say to intermittent fasting, so like eat from like noon to 6!? Which is what I have been doing. Confusing!

@Cubalibre-v6b 2 months ago

After watching a lot of videos of Dr Stacy talking about eating first thing in the morning I started eating within one hour from waking up. I started around three months ago, it was so hard the first week because I was not hungry at all and I refused to give up my hot coffee. I tried her protein coffee recommendation but my body wanted my morning hot coffee. What I do is I have my coffee and then I eat some Greek yogurt with at least 20 grams of protein powder , I go to the gym to do my workout and within 45 minutes to one hour after I have my breakfast.
LIFE CHANGING!!!!
I highly recommend getting her books !

@dianavp9054 2 months ago

I’m eating a ketovore diet to keep my carbs low, and because I cannot digest plant matter. The painful bloating and distension caused me to stop eating FODMAPS six years ago. For me, eating fiber has always been a constipating bloating disaster, yet everyone says to eat fiber. I’m 69. This has been a lifelong problem. 😭

@yvemarybmusic 1 month ago

Any tips for perimenopausal musicians! With late gigs! And best supplementation post gig to wind down. Ty

@MDCarr 2 months ago (edited)

So my take away - from everything I’m reading and listening to- is that my toolbox is very different than men. And it’s even more different now at age 55 than 25. Thankful for all the books and discussions around this topic that is female specific. It’s about damn time! GenXers - pay close attention - time goes by very fast.