Live Like a Girl with Dr. Mindy Pelz - Fasting Isn't Always the Answer. Here's How to Know When It Is.

Episode Date: July 8, 2026

For years we've been told that if fasting is good, then fasting longer must be better.That simply isn't true.Fasting is one of the most powerful healing tools we have, but it's also a stressor. Like exercise, the benefits don't come from the stress itself. They come from how well your body recovers afterward.In this solo episode, Dr. Mindy explains how to tell whether fasting is supporting your metabolism or pushing your nervous system beyond its limits. You'll learn the five green lights that signal your body is adapting well, the five red flags that tell you it's time to pull back, and simple ways to adjust your fasting practice based on your hormones, stress levels, and stage of life.Whether you're new to fasting or you've been doing it for years, this episode will help you stop guessing and start working with your body instead of against it.In this episode you'll learn:Why fasting is a beneficial stressor, but only in the right doseThe difference between metabolic stress and chronic stressHow your nervous system influences your fasting resultsFive signs fasting is working with your bodyFive red flags that indicate your fasting routine needs to changeWhy sleep, energy, hormones, and muscle are powerful feedback systemsHow to adjust your fasting practice based on your cycle and life stageThe importance of recovery, refeeding, and metabolic flexibilityWhy fasting should always be personalizedResources MentionedDr. Mindy's BooksReset AcademyBurn Fat Like a Girl: Your Natural GLP-1 ResetNervous System Free ResourceLMNTBEAM MineralsStandard Process EZ MagFor more resources related to today’s episode, visit the podcast episode page: drmindypelz.com/ep350Connect with Dr. Mindy:Join Reset AcademyWatch the episodes on YouTubeFollow Dr. Mindy on InstagramSubscribe to Dr. Mindy’s newsletterDisclaimer: This podcast is intended for educational and informational purposes only and is not a substitute for professional medical advice. Always consult a qualified healthcare professional before making changes to your diet, fasting routine, or lifestyle.

Hey, Dr. Mindy here and welcome to the Live Like a Girl podcast, where I bring you icons, disruptors, educators, scientists, and doctors that show you what can be possible when you love and celebrate the female body you are blessed to live in. Let's dive in. One in three adults are completely overwhelmed with their stress loads. looking at it through that picture, fasting might not be the best tool for a completely stressed out human. It doesn't mean fasting doesn't work. It means that once again, we need to think about if fasting is right for you. So in this video, I am going to walk you through five signals that your body will give you to tell you if fasting is working or if fasting is working or if fasting is not working. I call them green lights and red lights. And I'm going to show you five action

steps you can do to either modify your fast, stopping your fast, or do more fasting, depending on where your stress loads are at and how your nervous system is handling it. This is a video we've needed to do for you for a very long time. And I can't wait to dive into this. So here we go. Let's go. First, we have to say, just like exercise, fasting is a stressor. So that's not a secret. Hopefully you understand that it is a hormetic stressor. Hormesis is a good stressor. This is how fasting works. It applies just a little bit of stress on the system that causes your body to grow bigger and do better things, just like exercise.

When you go and exercise, if you are lifting weights, you break muscle down and that muscle is under stress, but it builds itself strong again. That's the same thing that's happening with fasting. But it's if you think about it, it's when we're already in a broken down overwhelmed state. if we put more fasting on top of that, that's not a good system. The stress that we put ourselves in, whether we fast, whether we exercise, whether we cold plunge or sauna, that is a signal, but it's in the aftermath of that, in the recovery where the magic starts to hit.

So think of it like your metabolic switch. Remember how I taught you about the metabolic switch? When you eat you're a sugar burner, there's no stress there unless you're eating the wrong food, like ultra-processed foods. But then when you switch over into fat burner, this is called your metabolic stress. Ooh, now we're adding some stress to this. And I think of it like a light switch, turning on and turning off. And somewhere around 12 hours without food, you will come over into this fat burning place and your body will start to go into this repair phase. Now, what's so incredible about the human body is that it

knows when it's over here that it needs to give you another fuel source. So it gives you ketones. And I've done a ton on ketones. I'm such a fan on ketones, especially for brain health, especially for postmenopausal women. So I'm over here in a fat burning mode. I haven't eaten in 12 hours, my body, my brilliant body, makes ketones. And it does that so it can supercharge the brain, but it does it so that it can preserve muscle. So those of you have heard, oh, fasting will break down muscle. Well, exercise and lifting weights breaks down muscle. And the beautiful part of the way the internal mechanisms are in our body is that the more ketones you make, the more muscle preservation that you will create. Now this metabolic switch, it is not meant to be turned on or turned

off all the time. If the metabolic switch is turned off, meaning you do not go into a fat-burning state, you have a tendency to gain more weight if you're not eating the right foods. If this metabolic switch is turned on all the time because you love fasting and you've been fasting over and over and over again, you also can go into a weight gaining place because the body is under so much stress. So why don't we fast forever? Why don't we do one meal a day over and over again? It's because these pathways, this glucose and insulin pathway, this autophagy and mTOR pathway, these all of the ways I've tried to explain it to you all over the years those pathways are meant to pulse they are not meant to be on all of the time just like we're not meant to have daylight all

the time or nighttime all the time there is a rhythm here that we're meant to to look at so the question is never is fasting good or bad it the question is how much time am i spending in the stress hormetic response and how much time am I spending in the recovery part and how am I mapping that to the stress of my life. This is where hopefully you've heard me talk about the end of one and how important it is that we take videos like mine. We take, or anybody's, we take books like Fast Like a Girl and we customize it for us and make it right for us because the whole reason I wrote Fast Like a Girl, the whole reason was to take teach the pulsing of fasting. And I find it comical that people think I'm the fasting queen

and that I just want everybody to fast all the time. I wrote a whole book on when to not fast. So let's come back to some sense of reality here. Now, you have a metabolic switch, but you also have a nervous system switch. One side of the equation for your nervous system is a parasympathetic nervous system. It is your rest and digest nervous system and it gets activated when we eat, except when we eat ultra-processed foods because there are so many chemicals in there that stimulate us. But when you're eating whole foods in a good meal, that you are hopefully in a parasympathetic state. And then when we fast, we go into fight or flight. We go into a little bit more of an adrenaline situation. So we have to map when we're looking at if fasting is right or wrong for you,

we also have to map where your nervous system is at. So if your nervous system is already locked over here in a fight or flight situation and you decide to do a 24 hour fast or you decide to do a 36 hour fast or a three-day water fast, that might not be appropriate for you because you were already in a fighter flight state. I have a beautiful questionnaire I just created that I'm using with my reset academy members and I want to pass it on to you. And it's called a nervous system reset. And there is a questionnaire in there. You take the questions, answer them. Do the, do, there's a scoring program there and look and see where your nervous system is at. Because if you're completely maxed out, fasting isn't your tool.

Now, I want to dive in to these steps of how do you know physiologically that you are meant to fast or you should maybe back away from fasting? Because I've seen this over and over and over again where one woman can do an 18-hour fast and she freaking rocks it. And another woman does an 18-hour fast and her hair falls out and she gains weight and she feels horrible. Let's, same fast, different body, different nervous system. So let's start to walk through these signs of how you can tell where you're at. I do want to say, if you want the nervous system reset questionnaire I have, just put nervous system reset in your comments because that is

a great gauge that I created to help you also see if you should be more in your sugar burner mode or more in your fat burner mode. So here is the first sign I want you to look at, and it's sleep. Woo. Okay, yep, we're going to go there. Are you ready? So your green light is that you fall asleep easily and you wake up rested even on longer fast days. That's a sign that you've, just like your metabolic switch is working well, your nervous

system switch is working well. I decide to go into a 24-hour fast. I'd maybe do a three-day water fast, and I'm pretty good. I sleep okay. I can tell you the first time I did a three-day water fast, I probably shouldn't have done it at that moment. I was testing all these tools out, and one of the symptoms that I had was a pounding heart, like a heart palpitations. I now know that minerals can help that, but if minerals don't help that and your heart is still pounding, it may be because your nervous system can't take the load of going that long without eating. I also have heard from many of you that when you go into these longer fast, you can't sleep.

And it doesn't happen to everybody, but it does often happen to the people that were already maxed with their sleep levels. And so what they need to start to do is a little shorter fast. We'll talk about that here in the moment. Now, a red flag with your sleep on your fasting days that would say come out of the fast is if you're wired at bedtime, you can't fall asleep, you're waking in the early hours and you can't get back to sleep, and specifically that day you really pushed your fast. Now, I'm going to leave another video that I've done on why you wake up at 3 a.m. And for some of you, it's because of cortisol. It's not, and you were already in that cortisol rich state. But I really want you to understand that, you know, you know, you

if you are fasting chronically and you're still waking up consistently at three in the morning, that we may need to just dial back on your spas a little bit. So ask yourself in this first question, this first sign is, does your sleep get worse on longer fasting days? Longer to me is something over 24 hours. And if it's yet, the answer is yes, that we need to dial back to shorter fasts. Okay, sign number two is your energy and your moods and especially in between meals. A green light is that you have a metabolic switch that is working really smoothly and you can go a significant period without food and your energy is steady, it is clear, it is calm, your hunger is quiet.

That would tell you if you're 16, 17 hours without food, that would tell you that you're doing great that you're that keep going. I've had some three day water fasts where I just felt great for three days straight. Some of you may have that. That's a sign that my nervous system was ready for that fast. If you start to fast and you get to that 24 hours or you get over 24 hours and you're shaky and you're anxious and you're irritable and you're foggy and you're hangary and you have trembling hands and you have a racing heart and you're snapping at people, you have gone too far in the fast and you need to start dialing it back. So adrenaline will send a signal to tell your brain that it doesn't have enough fuel. And so when adrenaline kicks in and you get the racing heart

and the shaking hands and your irritable and your OCD brain, that is a signal. Remember? Where it lab. So when that is a signal telling you that no food is putting your body in a crisis state. Not all of you will get that with fasting, which is why this is not a video on everybody stopped fasting. This is a video on how do we be the end of one of our fasting experience. So if you are crashing in between meals and your moods are horrible and it's time, to start to go back to the lower fast and build some base here. A 13-hour fast has great research on preventing a reoccurrence of breast cancer. A 15-hour fast does an amazing job for growth hormone and getting you more anti-aging, growth hormones an anti-aging tool and helping you burn fat.

A 17-hour fast is amazing for getting rid of those zombie cells that speed up age, aging and for getting rid of cancer cells. There's so much magic that happens in those lower fast. I wrote about all six of them, by the way, here in my book. But you might need to go back. It might not be, your body might not be ready for the longer fast. And that's okay. That's not weakness. That's actually straight. That's showing, you're showing your body, hey, I trust you. I got you. I'm listening to you. That is so important to come back into a positive relationship with your body. Okay, sign number three, this was the heart of fast like a girl. This was the whole reason I wrote this. And it's your cycle and your hormonal rhythm. So when I first started fasting and

falling in love with the science of fasting, using it as a tool with my patients, I noticed for my own self, I was in my mid-40s that my period was starting to stop and that when I did get my period, the symptoms were horrible and I was like having really big heavy hemorrhgene type periods. And at the time I thought it was perimenopause. But I had combined perimenopause with a lot of longer fasts. And so I was putting myself too much in this sympathetic dominant state. And so I started playing with wait a second. maybe there are times of the menstrual cycle that we should fast and there's times we shouldn't and that's

where I came up with the fasting cycle and this fasting cycle continues to be a resource that over a million and a half people have bought this book and have used it and you go look at my Amazon reviews so many people's cycle has come back because they discovered how to fast with a hormonal rhythm. I will give you three really simple ways to look at. look at your hormonal rhythm. If you are a woman who is cycling, you know, in your 30s, 20s, maybe in your teens, then you want to fast according to the fasting cycle. If you are perimenopause and your hair is falling out and you're spotting and you're irritable, you're going to want to stay to shorter fast, especially, you can really do it most, most of the cycle, but not the week

before your period and you're going to want to stick to lower fasts. If you are a post-menopausal woman, you can fast longer. Those ketones are really going to help you. So especially with brain. So same woman just aging along in different hormonal rhythms. And for my post-menopausal women, I have a whole chapter on fasting and ketones in age like a girl. Now, a green light with your hormonal rhythm would look like, I'm fasting, I'm doing the fasting cycle. I still have a cycle. The cycle is regular. It's predictable. My libido is fairly good. And I don't have a lot of PMS. That would tell you whatever you're, however you're fasting right now, it's working. A red flag would be that you're still cycling, but all of a sudden your cycle stretches out,

or it lightens, or you start skipping it, or your PMS is last. your sex drive is gone. Now, with postmenopausal women, a green light is you have a stable mood, your temperature, you don't get any hot flashes, you're not losing hair when you're fast. Whereas a red flag for postmenopausal women would be, oh my gosh, I've got more hot flashes, I have a racing heart, my hair is shedding, clumps are coming out, and a low mood is starting to creep in. So the brain senses when no energy is coming in and it protects you when it has gone a long period of time without fuel by shutting down reproduction. So your cycle, your libido, your hair, they are signs of fuel and how much fuel you're getting, are you getting the right amount of

fuel. And if you start to look at those as just indicator lights, just like we look at on our car, we can start to see if this fasting length is right or not right for us. So when it comes to hormones cycling your fast, whether you're postmenopausal or you're in your most fertile years in your 20s and 30s, there are times to fast and there are times to not fast. And understanding what's right for you is an art, which is why I wrote a whole book on it. I even have a membership group called the Reset Academy where women are in there learning how to make their own end of one experience there. You can join us over there and just put Reset Academy and we'll send you info on it. But more importantly, I just want to make sure you understand you're rhythmic. You have a rhythm and so

we need to have rhythm with our exercise, we need to have rhythm with our fasts. And one of the things that has really crushed my heart is that there is a rhetoric out there that menopausal women shouldn't fast. And they say that because their hair falls out and all a sudden as they're moving into their menopausal years, they're having really bad symptoms. But that's not the case. The case is that we need to learn how to pulse fasting in and out, in and out and match it to our hormones. Can I tell you something I wish someone had told me years ago? If you've ever tried to fast or follow any health program and it didn't work the way you expected,

I need you to know that it's not a discipline problem and it's not a willpower problem. It is an information problem. Most fasting research was done on men. Most dietary advice was designed for men. and then it got handed to women as if our bodies work the same way. And they don't. You operate on a 28-day hormonal cycle. And the foods you eat, the length of your fast, even your workouts, all of it needs to be

timed where you are in that cycle to actually get results. That's exactly why I wrote Fast Like a Girl to teach you. It's a step-by-step guide to using fasting in a way that's actually built for your feminine body. This book has been out in the world for several years now, and it just hit the New York Times bestseller list. That tells me something. People are still reading it. They are still getting incredible results. And I want to point out, this isn't just for women that are in their menstruating years. There is plenty in there for perimenopause and postmenopausal women. Because even then, we have a new hormonal balance we need to time our fast too.

If you're finally ready to understand your body at a new level, you can find fast like a girl wherever books are sold or at Dr. Mindy Pells.com slash books. So number four, I won't keep going on that one. Your muscle, your strength, and your shape will tell you if you are fasting too much. And here's what it looks like. So the green light with fasting, I want you all to hear this because I've done thousands of videos here on YouTube, on belly fat, on weight gain. It is a very popular topic here on my channel. When you are fasting correctly, you should lose weight. So a green light is that you can drop weight when you fast, just like the millions of people that bought this book and lost hundreds and hundreds of pounds. We just did in our reset academy, we did a two-week experience where we took 600 women through different fast cycling in, different fast foods, and the average weight loss was 5.8 pounds in

two weeks. That is healthy weight loss. You can join us. If you ever want to join us, just put burn fat like a girl in the comments, and my team will send you links for the next one. But more, again, more importantly, it was because I walked these. women through a rhythmic experience. Their food noise went down, they lost weight. That's a green light. Because they were taught how to have, how to use fasting to pulse in and out. A red light is that the scale actually doesn't drop when you fast. You may actually be going in the opposite direction, and you may be breaking muscle down. Ketones are supposed to preserve muscle. But it, when we move from a hormetic stressor into a chronic stress state, all of a sudden muscle will break down.

Your adrenal glands and your muscles use many of the same amino acids to function normally. So when you are asking your adrenal glands to constantly be on call, whether it's stress from your life, stress from a longer fast, and it doesn't have the right nutrients to do that, what it will do, is break muscle down. It will grab nutrients like amino acids from muscle to be able to support the adrenal glands. Now women over 40, a lot of what you're doing as you go into perimenopause and into postmenopause is your ovaries are asking your adrenal glands to work extra hard. So if you're a red flag would be, I can't lose weight and I'm losing muscle. That is not a good scenario and you're going to want to dial your fasting back a little bit. And again, easy signal to look at.

So another piece of this I want to point out is the thyroid gland. And the interesting part about the thyroid gland, another topic that has fasting getting lots of criticism. I have done multiple videos on here on the thyroid. And yes, T3 goes down. the bioactive version of T3 goes down when you fast because the body goes into an energy conservation state. But it doesn't, when you bring food back in, especially that first meal, when you re-feed in a really good way, what happens is you restimulate the thyroid and all the thyroid hormones start to come back into balance. It's like a reset. But if I'm a stressed out woman who's like, I used to get great results with fasting. I'm just going to do more of it. I need to do more of it.

And you're not getting that great result and your hair is falling out and your heart is racing. And you're not, the scale isn't budging. Then you are bringing those thyroid hormones. You're cold. You're cold hands and feet. You're bringing those thyroid hormones down to to a level that is not working for you. So again, this is why we pulse fast. fasting. So cortisol, by the way, that never comes down. Cortisol, when you're living in this too much fasting state, can also suppress the immunity. So if you're fasting and you're getting sick all the time, that's not great either. I've actually seen, I've seen more people have an improved immune system from fasting, not the opposite. But if you're getting sick a lot, you may be in this

this metabolic breakdown moment. Now, before I go into the six things, or the five things I want you do, I really can't emphasize enough. I do not want any of you walking away from this video thinking fasting's the enemy or saying, oh, Dr. Mindy changed her mind on fasting. There are little tweaks I have changed my mind on, not on all of fasting. I still think fasting is one of the greatest healing tools that we have and it is free. But we have to start. We have to start. to learn the art of cycling fasting, which is where I started with Fast Like a Girl back in December of 2022 when this book came out. It was the only fasting book that was teaching this cycling approach to female hormones. It is the dose of fasting that's the medicine, not the poison. And the right

dose is unique to you. Your dose of fasting and my dose of fasting, may be completely different. Your dose of fasting and your husband's dose of fasting, totally different. So don't fall prey to people saying women shouldn't fast or menopausal women shouldn't fast. They don't understand the power of pulsing fasting. Okay, here are the five action steps. I really want you to start to do. And these action steps are from easiest to hardest. First, I'm a huge fan of putting minerals, having minerals when you fast. Let's just, let's not put an extra load on your nervous system. When you lose minerals, now the nervous system is even stressed about that.

So let's get some elementy. I'll put, again, links. You can do these electrolyte packets. You can do the cans. There's all kinds of brands. I also like bean minerals. Again, all the products I love with discount codes will be in the notes. But let's put minerals in first and see if the hair stops falling out.

Let's see if the heart stops racing. And then you'll know, was it my nervous system or was it minerals? So that was number one. Okay, this is my favorite thing. I want you to know so bad. I keep doing videos on it. Please tell me if you're getting it, which is breaking your fast matters. That first meal matters.

It is the most important meal that you have. So breaking it fast matters. I like doing it the GLP one way, which is let's make sure we have fiber, protein, fat, and then some carbs. But you need that fiber to feed the microbes so they make GLP1 hormone. You need the protein so you can get the amino acids back in the muscles. You need fat so you don't end up with a big glucose spike. And then you can put your carbs in there to get yourself some serotonin.

So break your fast like it matters, like your life matters. Okay, number three is that you're going to match your fast to your hormones, your hormonal state. So I have a whole book on it. It's called Fast Like a Girl, if you're new to me. I wrote all about how do you fast your hormones for my postmenopausal friends. You can fast however you want. I like you more doing like a weekly schedule, like a 511 or a 421. I put protocols in here.

I really think that postmenopausal women do incredibly well with fasting. It's easier. And they get those ketones so that they can start to fuel their brain in a new way. And they get the muscle preservation. So, and again, if you need more information, dive into the books so you can find yourself or come join me in my academy. Okay, number four, I want you to track one objective signal for two weeks. Track your sleep, track your HRV, track your cycle, track your morning energy, track your ability to go without food, whatever it is,

track it. I've got a bunch of trackers. I can't reach it in my fast like a girl journal. You can write it all down. That was what the Fast Like a Girl Journal was meant to do. We'll leave links for that. But track something so you can see your progress. And you can see if you need less or more. Number five, if three of the signs I talked about are read, run what I call a deliberate reset, pull back on fasting,

and start to rebuild your sugar burner system. I want you to rebuild it with good protein, I want you to rebuild it with fiber. I want you to rebuild it with good fat. I have videos on how you can start to create a foundation with your food that balances your nervous system, but also will give you more GLP1 hormone. You make GLP1 hormone. That video is right here. You can go and check that video out. So, but more importantly, does. Dial it back. If you had three, you listen to those signs and you're like, I'm not sleeping. It's really hard for me to fast. My hair is falling out. I'm gaining weight. Dial it back and start over

by really getting that sugar burner system in place. I have a book that I wrote called Eat Like a Girl where I have so many recipes in here and lists of food come back to good eating and then go to fasting. Go back to fasting. It's amazing. how it works, or again, come join us in Burn Fat Like a Girl experience. Just put Burn Fat Like a Girl in the comments and my team will send you a link. So what I want you to say when you're not getting a good fasting result is I want you to ask yourself, is my body adapting or is my body struggling? because we want your body to be adapting to this metabolic switch, not struggling with it.

Now, I know a lot of you have friends that have been fasting, and if you have some or a spouse that's been fasting, send them this video because this, again, might be one of the most important videos I ever put out, and I want to make sure everybody is fasting in accordance with their biology. I want to make sure everybody is safe, and I want to make sure that you're getting the best of fasting, that it's not tanking. you into a chronically stressed state. If you've mixed your fasting up and you've done the rhythm, tell us your story so we can all learn from it. But most importantly, don't give up on yourself. Don't give up on fasting. It's just a few tweaks that is going to have you getting the results

again and making fasting feel effortless. As always, I hope that helps.