Flex Fasting: 8 Myths Debunked — Full Breakdown & Transcript

[00:00] Now, I've been teaching fasting for over 15 years, and I've been deep in the science for about that time. And when we first started to learn about fasting, there was a lot we didn't know.

[00:14] It kind of reminds me of the GLP medications right now. Like, we know that it helps for certain things, but we don't quite understand completely all the things it can do and the consequences of things like that.

[00:26] That was the early days of fasting, too. We had a lot of night studies. We had a lot of male studies. We still don't have a lot of female studies. And so we had to do a lot of interpreting of what the science said and then apply it to people.

[00:40] And we had to see what happens when people started to use this incredible tool called fasting. And so back for 15 years, after watching millions of people fast, I have some upgraded thoughts on it,

[00:52] which is why I keep doing videos like this for you so that we can make sure that you succeed at fasting. I still will tell you 15 years later and watching millions of people fast and writing lots of books on it and doing tons of videos on it, I am still convinced it is one of the greatest tools for metabolic health.

[01:13] Even greater, perhaps, than the medications because there's not a lot of side effects. but I do see that some of the things that we recommended early on in the fasting world,

[01:25] like skipping breakfast, really can be looked at much different. So if you're somebody who loves breakfast, if you're somebody who wants to eat before you work out, if you really are excited about influencers that are telling you that protein should be consumed in the first hour of every day,

[01:45] And I have really good news for you because there's an incredible study that I found that shows that the flexibility of your eating window is key for lasting results.

[01:58] So in this video, I'm going to break this study down and I want to show you many of the things that I've changed in watching so many of you fast and what this new study is providing me.

[02:10] And I will tell you, I'm calling them eight outdated rules, and I'm really rethinking the way that I teach fasting as more of something I call flex fasting.

[02:23] You decide. And I love this idea because if you are in charge of your health and you're making the decision, you're not making decisions based off of what I said or what your doctor said.

[02:36] You're actually involved in the decision making. You get a better result. And that is what the research is showing. So here we go. What was this big study that changed my mind?

[02:49] So it's a November 2025 random controlled trial study in nature's communication. And it tested 104 women between the age of 40 and 60, and it looked at them over a 12-week period.

[03:08] And here is what they did. There was one group that did a very specific style of fasting. I cannot find in the research what the control group did behind the paywall, but it didn't do what I'm going to tell you got the best results, which is there is an eight-hour eating window.

[03:27] They asked these 104 women to find an eight-hour eating window, and they could move that eight-hour eating window any way they wanted. They could slice it any way they wanted it.

[03:40] So one day it could be in the morning and the next day it could be in the afternoon. They said just be flexible with that eating window. The only requirement was that you need to, they had to eat breakfast somewhere between 8 a.m. in the morning and 12 p.m.

[04:00] And they had to finish eating somewhere between 4 p.m. and 8 p.m. and they had to do some form of moderate aerobic exercise.

[04:12] Okay, I just want to stop there for a second because, man, are we getting the message these days that cardio doesn't work for us? Exercise, we have to lift weights to lose weight. And what this study is saying is if you combine moderate aerobic exercise

[04:29] with this flexible fasting window where you take an eight-hour fasting window and you put it wherever you want, you make a decision and you can change it every day, that that was a better result than people who kept a rigid window and perhaps didn't exercise.

[04:49] Again, I don't have all of the specs on that, but I know that they tried to keep people at the control group, kept people at one specific eating window. I'm going to come into this in a moment because this is really, that's a key piece.

[05:04] So here's what happened. When they were able to take this flex window and move it around with moderate aerobic exercise, they lost 6.6 pounds greater fat mass reduction than the control grip.

[05:22] and the adherence, this was a 12-week program, the adherence was 83% to 87% proving that women can sustain this if they are given flexibility.

[05:37] Now, what's really crazy about this is that the study, what they were looking at was the meal timing lever. They wanted to see if we gave people the flexibility of that meal timing,

[05:50] would they stick to it more and be able to lose more weight? And because the common hurdle for fasting is this rigid same meal timing where you're eating in the same way every single day.

[06:06] So a lot of you do 12 p to 8 p as your eating window and every single day And what the research is showing is that it actually works better if we move that eating window around which was really the beginning of what I was trying to teach you all

[06:24] with Fast Like a Girl was change your fasting rate. And what this research is saying, change your eating window, change when you do it. So my number one rule is you pick your eating window,

[06:38] You decide, and you can change it every day. If you want to eat before you work out in the morning, eat before you work out. Shut the eating window down at the end of the day a little earlier. If you want to eat with your family at dinner at night, maybe you're going to push that eating window.

[06:54] You're going to open it up at 12 p.m., not 9 a.m. You choose your eating window. So if you follow influencers who say you should eat, always eat in the morning,

[07:06] than eat in the morning and block it off earlier in the afternoon. You are in charge of you, and the flex fasting principle is you decide the eating window that's right for you. Number two, rule number two, myth number two that I'm undoing,

[07:22] that when you are in the fasted state, you're to drink water only. I have changed that opinion. I have done many three-day water fasts myself where I've had just straight black coffee with no cream

[07:37] because I didn't want to get off caffeine. We are big fans of elements. I really recommend that you put some minerals in your water or even into your coffee.

[07:52] I've even recommended creatine, and this is our favorite, is qualia creatine in coffee in the morning, black coffee, to add that creatine in. We do know from research that fasting triggers sodium loss through the kidneys.

[08:10] And a lot of times when we are getting into a place where we are feeling dizzy, it's just because we need some minerals. So you can put, you can get some elements. I've been a big fan of bean minerals.

[08:24] These are great to do in your fasting window. Fasting windows don't mean water only. They mean black coffee if you want black coffee. Helps stimulate autophagy.

[08:36] We're going to talk about this in a moment. It means minerals. If you want some added taste, you can do some elements. Or if you're not feeling well, you can grab yourself some beans. You could do mineral water. You could do tea.

[08:50] There's a lot of flexibility of what you can drink. You could drink iced tea without any sweetener in it. That can all be in your fasting window. Now we're flex fasting. We're picking our eating window and our fasting window.

[09:05] We get to have a few possible taste changes and drink a little more. Okay, rule number three is we used to think coffee and tea broke your fast. I kind of already explained this, that the research shows that coffee can stimulate autophagy.

[09:22] And autophagy helps clean those cells out. The research actually shows one to four hours after consumption, you have this big burst of autophagy. I don't know. I'm not opposed to coffee, even in a three-day water fast.

[09:37] I really think it can help stimulate autophagy. And it's not, it may even amplify it, and it's not breaking your fast. So if you feel like you need to do your coffee, do your coffee.

[09:53] Now, number four is really interesting. This one I have not brought to you yet. And I really want to have a roll up our sleeves and have a serious conversation about this because somewhere out there, people think that I am an advocate for longer fasts.

[10:09] I, in my mind, have separated fasting into shorter fasts, which is anything under 24 hours, and longer fasts, which is anything over 24 hours.

[10:22] And I think of longer fasts as therapeutic tools. They are tools for people who have really damaged guts, people who have really stubborn weight loss, people who need to reset their dopamine pathways, and people who want stem cells.

[10:38] So you use them periodically. I am not recommending that you double down on these longer fasts. The shorter fasts are maintenance fasts. These are ones you can do every single day.

[10:52] I'll go through when you kind of do both. But really the shorter fasts are anything under 24 hours that you're using as a regular tool. So I'm not saying that longer fasts are better.

[11:06] I'm saying that they are used differently in my mind. And I do not believe that if you don't get a result, just keep fasting more. There's so much nuance to this.

[11:19] And if you want to know how to customize some of the longer fasts, you can come into my Reset Academy and we're helping people over there. And for the sake of this conversation, I want us to really pull these two out.

[11:31] And there's some interesting things to bring out. We do know, and this is one of the criticisms of fasting, is that it raises cortisol. And the longer the fast, the more cortisol that goes up.

[11:46] That can be difficult for women. But there was a 2016 meta-analysis that showed it was the prolonged fasting, the over 24 fasting, that elevated cortisol, not the shorter fast.

[12:03] I want you to get this because so many of you asked me about this. So if you're in a chronically stressed state, you can do the shorter fast, anything under 24 hours.

[12:16] But if you are in a chronically stressed state, don't go over 24 into those longer fasts. If you are moderately stressed and you want to do the longer fast just do them once a year maybe twice a year because what we know is cortisol levels will return afterwards That the nuance Now shorter fasts

[12:39] Here's what shorter fasts are. To me, a shorter fast is somewhere between 13 and 17 hours. And this is great for metabolic flexibility, to prime our metabolic switch, blood sugar stability,

[12:54] to make sure we're not on the up and down blood sugar roller coaster, brain function and mental clarity, because now we're getting ketones, and we like ketones for our brain, hormonal support for menstrual cycle

[13:10] and even into menopause and the transition. Go look at my Amazon reviews on Fast Like a Girl. There's over 8,000 reviews. and so many women talk about how this the fasting cycle that I mapped out in there

[13:26] helped get their hormone balance back and these were a lot of them were perimenopausal women so it's the shorter fast that I show you how to flex in and out of in the fasting cycle

[13:41] Now, longer fasts, this is 24 hours or more, so 24 to 72 hours, are right for stem cell renewal. For autophagy, when we want to get a deeper level of cellular cleaning, to break metabolic plateaus,

[13:59] to help clean up after we've been taking a lot of medications or illness or antibiotics, or we've had a stressful season. For immune system reboot, these fasts are not meant to be done on a regular basis.

[14:15] They are healing tools when we need them. So I hope you see the big difference here. Okay, myth number five that I would like to break is pushing through the hunger.

[14:29] Okay. Okay, old me was like, let's get, we just think about what the hunger is and try to become friends with it and you can keep going. And the new me is hunger is data.

[14:44] So this one's really interesting because when hunger is off comes in, real biological hunger, a lot of times in fasting, it means cortisol is going up

[14:56] and our thyroid hormones are dropping and the microbes in our gut are asking for fiber and food and your minerals are depleted. It is a state of crisis in that moment.

[15:10] True hunger. When you haven't been eating. Not emotional hunger. So just true hunger. And what was interesting in this random controlled trial that I showed you where they changed their eating window,

[15:23] What happened is they found that women on the flex fasting technique, where they had flexibility of wanting to go in and out of these eating windows, that they spontaneously ate less without being told to restrict their food because the window itself naturally curbed intake.

[15:45] It was honoring real hunger that fasting can't always honor because you chose your eating window. Okay, what does this mean? This means if you are notoriously hungry in the morning, you get to put your eating window in the morning.

[16:03] If you are notoriously hungry at night, you get to move that eating window. The flexibility of moving that eating window around really made a difference.

[16:15] Now, what the study didn't say is that there are some hunger hacks, and they are things like have a tablespoon of olive oil or two. That can often kill the hunger going on in the brain.

[16:30] Sometimes even a little bit of a pack of minerals will kill hunger. MCT oil in your coffee in the morning can kill hunger. you'll see that a lot of these changes I'm making in this flex fasting approach, they overlap.

[16:48] You can pick your eating window. You can have coffee. You can have other things. And they can be tools for the experience to make it easier for you. So if you feel shaky or dizzy or anxious or wired, you have options.

[17:04] You have lots of them. I just gave many of them to you. Okay. Myth number six. This is my new one that I just am going to keep educating us all on, which is the idea that fasting alone will transform your body.

[17:21] There is something really important about knowing that when you are in the fat burner state, where you are fasting, that's only one half of the metabolic switch. Remember, there's a sugar burner.

[17:34] So you need to be able to come over into the sugar burner state. So we've got to be able to move back and forth. Both fat-burning state and sugar-burning state are really important.

[17:49] In the flex fasting approach that this 25 random controlled trial said, is they said, don't give up on exercise. Don't give up on cardio. It's not a bad tool.

[18:02] We're going to use it with fasting to be able to lose weight. So they, in that article, combined fasting with moderate aerobic activity. That's an example of saying you can't just not eat and hope to lose weight.

[18:18] You've got to combine it with exercise. Now, one of the things that has been really helpful if you are going to exercise in the fasted state is creatine. Put creatine in your coffee.

[18:30] Put it in your water before you go to the gym. if you were in the fasted state and you were giving your muscles food that it needs. So perhaps your flex fasting would look like I fast then I go lift weights I put my creatine in my coffee before I go and lift weights and then I eat protein in my recovery meal

[18:55] These are all options that I hope that you're understanding. The other one that's really big that I'm going to keep talking about is how important when you reintroduce food.

[19:07] The refeed is massively important. I've got a whole video on that. It's as equally as important as the fasting window. So, again, are you seeing there are options here?

[19:20] Okay, number seven is this is interesting, that we're back at the eating window. Stick to your eating window no matter what. So this was an interesting, a different 2025 research study of over 6,000 users,

[19:37] so it was a big sample size, and said that when your blood sugar drops, when the glucose drops below a personalized threshold, hold, let me put it in your terms.

[19:51] If glucose drops below 70 and you feel like you need to eat, if that glucose has gone below a threshold, 70 is the threshold I've given you all.

[20:03] I want your glucose to be, when you're in a fasted state, somewhere between 70 and 90. That if you still, if it drops below 70 and you decide to end the fast early, that there was still meaningful weight loss that occurred and glucose improvement.

[20:22] so in the flex fasting idea what protocol what we're saying is if blood sugar goes low you are feeling dizzy you've tried all the tricks and you're like but I was gonna go five more hours

[20:37] I was gonna go three more hours you will still get the benefit especially if it's weight loss if you end the fast and then you'll the other thing is you'll be able to continue your fasting lifestyle over time because you will have had a great experience. It got difficult,

[20:56] your blood sugar dropped, you ended the fast, you're still getting glucose improvement, and you're still losing weight. This is data over dogma. Okay, number eight, y'all know I love this

[21:10] one, which is the same rules apply for women. Okay, how many of you have heard that fasting tanks sex hormone? If you have heard that, I'm going to clean this up right now. So a 23 study

[21:29] in obesity looked at four to six hours of time-restricted eating in pre- and post-menopausal women and they found that there was no significant changes in key sex hormones, estrogen, progesterone,

[21:45] and testosterone. So the fear that fasting will wreck women's hormones is inaccurate. According to research, there was a four to six hour eating window in pre and post menopausal

[22:00] women. So now I gave you the fasting cycle. I also recommend you change, you move your fasting around, you move your fasting length around.

[22:12] Now you know you move your eating length around or your eating window around. And so part of flex fasting is making sure that you have the tools to do something like stabilize your hormones.

[22:29] I'm still a fan of don't fast the week before your period. But the research is even showing that even if you do four to six hours of an eating window, it does not tank your sex hormones.

[22:43] So let's take that off the plate. So flex fasting is really built for exactly this. It's built for cycling women. It's built for perimenopausal women with all this erratic cycle.

[22:57] It's built for menopausal women that need more ketones. It's built for people who are trying to maybe get off the weight loss drugs. You have flexibility of how long your eating window is, where you put your eating window,

[23:11] what you drink in your fasting window, how you exercise in your fasting window. You have flexibility over what you do with how you break your fast.

[23:23] You have flexibility over if you fast before a workout or not. That is flex fasting. You are in control. Here's all the possibilities. You customize it for you.

[23:35] That is what I'm teaching. Here are the five steps I want you to think about. One, flex your fasting window every day. If you're doing 16-8, change that eating window however you want it.

[23:49] Number two, always mineralize. Make sure in your fasting window you're getting plenty of minerals. Number three, eat protein. We like protein. When you eat, eat protein at every single meal.

[24:03] Number four, when you refeed, I will leave the link to the refeed video here. Refeed your microbiome with things like fiber and fermented foods.

[24:16] And what this study has showed us is you can pair fasting, especially the shorter fast, with movement. and you can get a moderate movement and you can get an even greater weight loss result.

[24:30] Okay, let me know. Is that helpful? I see it all over the Internet that people are trying to say, I tell everybody to skip breakfast, I tell everybody to do longer fast. That is not what I stand for.

[24:42] I stand for flex fasting and you customizing it so you can stick with it over time because I know the result will give you, will reap you incredible benefits if you stick with it.

[24:55] I don't want you white knuckling this. I want you to customize it for you. As always, I hope that helps. If you like this video, you're going to want to check out the next one.