Episode 149 | 14-Day Water Fast: Fat DOWN, Muscle UP ft. Dr. Christy Kesslering

[00:00:00] Dr. Katie Deming: Everyone warned her that a water fast would strip the muscle right off her body. Then she ran the scans, and the numbers told a completely different story. Welcome to Born to Heal, the podcast helping people with cancer go beyond Western medicine to heal naturally through the ancient power of prolonged water fasting, so you can ditch the toxic protocols, take control of your health, and let your body do what it's designed to do: heal. I'm your host, Dr.

[00:00:30] Dr. Katie Deming: Katie Deming.

[00:00:31] Dr. Katie Deming: Today, I'm joined by Dr. Christy Kesslering, a fellow radiation oncologist who left conventional medicine to focus on metabolic health and data-driven testing.

[00:00:40] Dr. Katie Deming: She fasted with me for 14 days, tracked everything before and after, and what she found gave her first-hand insight into what her own clients experience when fasting. In this episode, you'll discover what her body composition scan showed after 14 days without food and why it flips the biggest fear people have about fasting on its head.

[00:01:04] Dr. Katie Deming: You'll also learn what started happening to her skin, her back, and her toxin levels around day four, and what that discomfort was actually telling her. And finally, you'll hear why her insulin climbed in the middle of the fast and the surprising process Christy believes that was rise was pointing to.

[00:01:25] Dr. Katie Deming: This episode is about what your body is really doing when you finally give it the space to rest. Let's dive in

[00:01:32] Dr: Dr. Kestler-Ring, welcome back to the show. It's so great to have you

[00:01:37] Christy Kesslering, MD: Thank you for having me. So fun. Love it

[00:01:40] Dr. Katie Deming: I love it. Well, and now we're gonna have a different conversation today, which I think is very exciting for people, is that, Dr. Keslering fasted with me for 14 days and has had her own personal experience of this. And what's beautiful about this, and, you know, I think it'd be helpful for people to know, I know you've been on my show before, but to describe a little bit of your practice to explain why I'm so excited to have someone like you have fasted with me, and then we have data about it that we can discuss.

[00:02:10] Dr. Katie Deming: So tell people what you do generally and so that then it kind of frames this conversation.

[00:02:17] Christy Kesslering, MD: Yeah. So I am also a radiation oncologist, kind of turned metabolic health. Um, very interested in trying to help the body heal itself. we know that, uh, you know, sadly, conventional medicine is more about treating the symptoms than trying to reverse the cause of those symptoms. So I left conventional medicine over four and a half years ago.

[00:02:40] Christy Kesslering, MD: I think that's so crazy. And I've started this, you know, telehealth kind of coaching business. Um, I'm not really acting as anybody's doctor, but really trying to get data. So my– It's KESS RX and Data Driven Health, so we, I, we, I run these lab panels to really look under the hood because so many people, how many cancer patients say, “I felt great, and then I got cancer,” right?

[00:03:04] Christy Kesslering, MD: Or, “I was feeling fine until this happened.” But really, our body's been telling us things along the way that we just don't really think about as our body talking to us. And many a time, I will say a h- I will always say, a healthy body doesn't get cancer. So what was happening in that body? And whether– And we know that sugar's a big player, and, and insulin resistance, and toxins, and mental, emotional, and living in fight or flight, and so there's all these different avenues.

[00:03:36] Christy Kesslering, MD: Now, I have, you know, some of my clients do some fasting, or we do a lot of fasting around chemotherapy for people who are doing that, or maybe some– We always are doing ketogenic diets and maybe we're doing some intermittent fasting to get into slightly deeper states of ketosis around radiation therapy or, or, or other tools.

[00:03:55] Christy Kesslering, MD: But I have sent, or h- we've had some mutual clients doing extended fasts and, and the– One of the main reasons we decided to do it, you know, I decided to do it with you after we have, you know, become kindred spirits, is that I wanted to understand what my clients were going through when they did it.

[00:04:14] Christy Kesslering, MD: I wanted to really understand. I'm like, because I cannot not… You know, I cannot eat. Like, I can fast. That's not hard for me. I haven't ev-ever done an, a more extended. I had done, you know, five days. I had done that as a dry fast, which in theory maybe gives you a little bit of a bigger benefit. But again, that was me being a doctor and supervising myself, and I love the fact that you have this supervised program because I think people can get into trouble, and there are a lot of nuances to fasting.

[00:04:45] Christy Kesslering, MD: But what I loved about your program, which I didn't know until I was in it, right, is, wait, I can't work? I can't check my email? Like, I am the sole practitioner of, you know, it is me, myself, and I, and how am I gonna keep my business running and how, you know- I- I'm, I'm way too important to take time off, and, and really it was a beautiful experience to not being tied to your phone or your pager.

[00:05:13] Christy Kesslering, MD: You know, like back in the day, like we never could get away from work, and as soon as they could get us 24/7, even on vacations, even when you had a doctor covering your clinic, they were still calling you. B- because either A, they didn't even bother to check to see if you were out of town, or they wanted your opinion, not the covering doctor's opinion, right?

[00:05:31] Christy Kesslering, MD: And, and now that I'm in my own business and I, I'm like, “Can I do this?” And I'm… And so I, you know, lived with that idea and I said, “Well, how am I going to do this?” If I'm gonna do this fast, for 14 days is what I decided on, because I was really looking more for kind of a detox, maybe some mental, emotional work.

[00:05:55] Christy Kesslering, MD: Not that I felt like I had anything, but you know, I'm definitely the workaholic kinda person and, you know, the… I'm also the people pleaser. Like, that's why I had lots of administrative responsibilities in my old practice, is I was always like, “Sure, I'll do that. Sure, I'll do that. I'll do that.” You know?

[00:06:12] Christy Kesslering, MD: Like, yes, because if I give it to somebody else, they won't do it the way I want it to be done, right? So not very good at delegation. anyway, and, and I felt like the program made me, yes, get off my h- I would say very commonly, “I'm on my hamster wheel right now.” Like, I would literally say that to my family saying I can feel that I am overworked right now.

[00:06:34] Christy Kesslering, MD: Like I had to put in all of these stop measures to keep myself sane, and, but I learned a lot in your program about how I can set boundaries, how I can separate my work life, my work and family life, my fun life, you know, like how do I keep those things very separate? and I also did go through a lot of detox, so we can talk about that when we talk about my experience.

[00:07:01] Christy Kesslering, MD: But yes, I like data, and so I did a few things. So I did some baseline labs, far bigger panel than what you want to see. I also did a body composition scan, a DEXA scan, so that I could look at body fat, muscle mass, bone density, visceral fat, all of these things like we hear very commonly out there online that you shouldn't do a water fast because you will lose muscle, and when you're older it's so hard to put muscle back on, it's not recommended.

[00:07:35] Christy Kesslering, MD: and then I actually did some additional labs during the course of my fast, during my refeeding, and then at six weeks post-fast, I repeated the DEXA scan, I repeated,labs. But I also did a couple other panels and, and I think it would be fun to talk about my toxin panel. I didn't know that I was gonna have the variety of detox type symptoms during my fast, so I unfortunately did not do a toxin panel right before and right after.

[00:08:07] Christy Kesslering, MD: So it's a pretty big delay in them, but I still think it's valuable talking about those. and I, and I love the body composition data that we have, and that will be very powerful and meaningful to people. But then again, we can talk about a few labs that why do they do this or that? And, and again, everybody is gonna have slightly different changes based on their experience and what is happening to them during the fast.

[00:08:36] Dr. Katie Deming: Beautiful. So you came in, you were like, “I wanna experience what my clients go through. What is this really like to go through a supervised water fast in this manner?” Looking for detox really was like from a physical perspective, experiencing that, and then really looking at, okay, what is my data? And like getting some before and after because your, like you said, your business is data-driven health, Kesler- Kes Rx.

[00:09:03] Dr. Katie Deming: So, let's dive into… Let's just start with the body mass, because I think that's the biggest question that people always have, like, just like you said. Y- and actually I love… Tell the story that you were just on this cruise and, like, you heard the same thing on, you know, and this was, was it a low carb crew or was it a

[00:09:18] Dr. Katie Deming: carnivore?

[00:09:19] Christy Kesslering, MD: it was a low carb. So basically it's a cruise, but a group then does an educational course. So all of your at sea days, you're in the classroom, you know, with all the speakers, and then on your, you know, excursion days, your, your port days, you're doing fun stuff. But it was great.

[00:09:37] Christy Kesslering, MD: There was a lot of different speakers coming at it from different avenues, but I heard it multiple times that, and, and it wouldn't be the first time I heard it, that you shouldn't do a water fast because you'll lose lean mass. And I said, “Wait a minute. I have data contrary to that.”

[00:09:53] Dr: Yeah, so let's talk about your data

[00:09:56] Christy Kesslering, MD: Yeah. So during the fast, I had a, uh, an InBody home scale, so it's not perfect.

[00:10:01] Christy Kesslering, MD: It's using impedance. we noted in that, that my body fat did go down quite a bit. So we, the body fat percent actually decreased on that. Again, it's not exactly the same as my DEXA scan, but the body fat percent went down, like, 7%. and then the body, uh, the, the the muscle mass, so it specified.

[00:10:27] Christy Kesslering, MD: So the muscle mass went up one pound. So muscle went up a pound on, based on bioimpedance. So number one, it does not appear that I lost any muscle mass during the actual fasting. When we looked at the actual DEXA scan, again, comparing the before and after number. So before was literally the week before I did the fast, and then the second number was, six weeks after the fat, after the fat, af- yeah, six weeks of full refeeding, I mean, full normal eating after the fast.

[00:11:08] Christy Kesslering, MD: and I– And just for reference, my diet is an animal base, so mostly carnivore-ish, ketogenic diet. So I tend to eat 70% to 80% fat most of the time. Now, leading into the fast, I was doing a slightly different variation of a low carbohydrate diet, so my beginning numbers aren't quite my typical numbers.

[00:11:29] Christy Kesslering, MD: But that being said, as soon as the refeeding was over, I went back to exactly that same way of eating. I also do lift weights. We were not lifting weights during the fast because we are taking it easy, so I was just doing some gentle stretching and lymphatic, you know, massage or, or lymphatic exercises and wa- walking the little bit that I got.

[00:11:51] Christy Kesslering, MD: So I wasn't doing any lifting. The refeeding, I started to bring back body resistance, and then light weights by the very end, and then by the next week, I just went back to regular weights, but, but I did probably take a week or two to build up to where I was. And the body composition scan showed that I did ultimately…

[00:12:10] Christy Kesslering, MD: 'cause, uh, you regain weight, so I'm gonna expect to regain weight and regain some fat. I did my total body fat loss between the start and the end on the body composition scan was a 4% body fat loss, which, uh, which was about six- pounds of body fat, six and a half pounds of body fat, but my lean mass went up pounds.

[00:12:37] Christy Kesslering, MD: So lean mass went up in a post-menopausal 58-year-old woman three and a half pounds after a 14-day water fast with a seven-day refeed. So not eating my normal calories for 21 days. I thought that was pretty impressive. And it's not like I, oh, I never lifted weights and now I started lifting weights. I've been lifting weights, you know, since I was 39 years old pretty religiously.

[00:13:04] Christy Kesslering, MD: So it was– And, and going back, I was looking at my lean mass 'cause I've done a handful of these scans over the last 10 years. 10 years ago is when I had 90.6 pounds of muscle mass. So I'm like, wow, I just, I just aged backwards, you know, 10 years.

[00:13:26] Dr: this is remarkable. Like, not only did you not lose lean body mass, your lean body mass went up. And actually, another thing that I think's important to hit for this with people, and this is my experience, but then I want you to tell people what you actually saw on the scale. Most people who start around a weight that is close to their ideal weight, which I would say within five, plus minus five pounds of that, they'll lose the weight during the fast.

[00:13:53] Dr: They'll lose the majority of the weight in the first week, 'cause a lot of that is water weight with the glycogen as you're, you know, depleting glycogen stores. But basically, they'll lose typically around a pound per day for the, you know, like 14 days, but it doesn't happen linear like that. It's like usually you lose m- more of it upfront and then it kinda slows down.

[00:14:12] Dr: But generally a p- about a pound per day. And then most people, if they started at a weight that was good for them, they will regain plus, like within five pounds of that weight within six weeks. So if you'll tell us how, like how much you lost and then how long it took you to regain it, because this is another piece as we talk about this, you lost mus- you lost fat, but then you put on muscle mass.

[00:14:39] Dr: So actually, you know, this preferential loss that when you regained it, you didn't regain fat, which often happens when people diet. You know, like when people diet, they lose like maybe some lean body mass, they lose muscle, but when they gain it back, they, they actually gain fat. And what you're describing is actually something different.

[00:14:57] Dr: So tell us, walk us through those numbers of your, the weight that was lost.

[00:15:01] Christy Kesslering, MD: So I'm just looking at my log to see it. So it, it is, you know, maybe, some days I would lose one pound and maybe a half a pound and whatever, but I even lost like I, I– what I lost like 11 pounds during the fast, then I kind of regained a little, but then I lost a little, so there was a little up and down.

[00:15:22] Christy Kesslering, MD: With all of my, refeeding and regaining, I– what I– I'm a– within a pound of where I started. So I am like, if you could even count a half a pound, you know, like who knows? Like we have such variation. But I would say consistently I'm about down a pound from what, from before I started.

[00:15:44] Dr: what you just described is exactly… So you lost 11 pounds, right? 14-day water fast, lost 11 pounds, and then the, you're gonna regain at different rates, but by six weeks after the fast, after refeeding, or like six weeks from the fast, including the refeeding, you were back at within

[00:16:02] Christy Kesslering, MD: 10 pounds, yeah. So like back up 10 pounds.

[00:16:05] Dr: Yeah. And

[00:16:06] Christy Kesslering, MD: the body composition, right? Because how do my clothes fit? Ha- you know, so definitely my clothes fit a little bit better. So I, again, lost essentially six and a half pounds of fat and gained three and a half pounds. Now, that was on the body comp, where I, again, I don't think that those weights, like you go in the middle of the day or here or there, but again, I would say that, that if I had to do the math, right, maybe I lost four pounds of body fat and gained three pounds of muscle, something in that, right?

[00:16:40] Christy Kesslering, MD: ‘Cause I'm down one pound, but I can tell that my body composition is a little bit different.

[00:16:44] Dr: Yeah, so this, this is really important for people to understand because the story that, that we're being told or the fear that is being put in people is don't water fast because you're gonna lose lean body mass.

[00:16:58] Dr: But actually, this is the opposite of what we see with calorie restriction, with typical weight loss. You know, if someone loses the weight, then when they regain, you're gonna actually have a shift towards less lean body mass and more fat. And what you experience and what I've seen with other clients is the actual opposite of that in here.

[00:17:18] Christy Kesslering, MD: Yeah, definitely. And again, I think that, that when we lose weight, no one is really doing it with extended fasting. Most people are doing it with either [00:17:30] short-term fasting, you're losing glycogen, it looks like your muscle mass goes down because again, like your analogy, you're wringing out the sponge, right?

[00:17:37] Christy Kesslering, MD: So it looks a little bit lighter even though it's still the same mass. but I, I feel like most diets are just calorie restricting you, and when you calorie restrict, you tend to, And, and that's why I like your refeeding, right? Because you're, you're essentially reverse dieting back up to a good calorie.

[00:18:02] Christy Kesslering, MD: what often happens in diets is you do it, and then you go back to eating the way that you were, and your basal metabolic rate has really slowed, and all of a sudden you're bringing in all this excess calories and your body's like, “Oh, thank you. We've been waiting.” You know? Like, “We've been slowing everything down because there hasn't been calories.”

[00:18:24] Christy Kesslering, MD: And then you kind of, what do… We don't store energy in muscle, we store energy in fat. And so it puts it back on in fat going, “Okay, I– we're ready for that next famine. We're ready.” You know? so, sadly, we, we need to look at that. And I do see that happening in all kinds of diets. So there are people out there following low carb diets, and they don't feel hungry, and they start undereating.

[00:18:48] Christy Kesslering, MD: But guess what? They get tired. And I'm like, tired means hungry, means you're not bringing enough f-fuel in. And so, kind of retraining the brain because I think we've just been so brainwashed that it's all about calories, so anytime we're not hungry, let's skip eating. And that really can mess with the metabolism and mess with how you then store when you do end up eating.

[00:19:12] Dr: Yeah. And this is what's interesting is that with a prolonged fast, this is different, right? We're not just restricting and continuing to do, this is also why we're resting, right? So when you're in this state, we're really sending the message to the body, we're resting, we're conserving. And then like you said, as we bring the food back in, it's like we're reverse dieting.

[00:19:31] Dr: We're bringing you back up, your weight gain, you know, and not having this push into fat is also another sign that we haven't down-regulated your met- basal metabolic rate by doing this prolonged fast, which I think people worry about. They're like, “Oh, I'm worried I'm gonna balloon up after this.” But when it's done in the right way, this should not be the case.

[00:19:54] Dr: You shouldn't be ballooning up, and gaining a bunch of weight

[00:19:57] Dr: after the

[00:19:57] Christy Kesslering, MD: n- no. Uh, except I will say that I've seen a couple where they go back to kind of a higher carb diet, which raises insulin and starts putting fat back on. So my bias is we should continue in a very low carb ketogenic way of eating, and that is what actually is the magic, of keeping our, our fat down and our muscles up

[00:20:22] Dr: Yeah, absolutely. and obviously you and I are on the same page. It's like, yes, if we are eating carbohydrates and we are, doing these, you know, things that we know from a metabolic standpoint are not going to be, beneficial in terms of your insulin, insulin resistance and all that, y- you're gonna put on weight.

[00:20:40] Dr: So absolutely.

[00:20:41] Christy Kesslering, MD: Right. Right

[00:20:42] Dr: I wanna jump into, the, the rest aspect of it and the mental emotional piece, because I remember this. Because we, you and I talked about doing a fast, it was like in the end of 2025, and you were like, “I wanna do this. I've got a plan around it.” So we were setting the date for like April, and you were like, “I know you say rest, but like I, I mean, I'm, I'm a solo practitioner.

[00:21:07] Dr: You know what that means. Like I- you don't really expect that I'm gonna do that, that like I have to rest.” And I was like, “No, I absolutely do.” So I'm like, it may not

[00:21:17] Christy Kesslering, MD: the reason, the reason that we planned it so far out was because I didn't have any patient that I– That was the first three weeks or two weeks 'cause I didn't realize, oh wait, we're supposed to rest during refeeding. So it was the first two weeks where I didn't have anybody scheduled yet.

[00:21:34] Christy Kesslering, MD: So, so it was easy to block my schedule, and then once I realized that, oh, in the refeed we should not just jump right back into working full-time, right? Because you're still recovering and you're– I was still detoxing, and we can talk about that. But, so I, it was very easy. Like, my clients were so great, and I just moved a bunch of them, and I only saw a couple at the very end of the week, and, and the only thing I did was start to…

[00:22:03] Christy Kesslering, MD: I would spend a very small amount of time each day of the refeed catching up on emails and chat messages and labs and things like that. So it, it, yeah. I didn't know that I could do it, but I made my workarounds. I, you know, had one of my, daughter that's headed to medical school, I said, “Here are the four things that you need to look at.

[00:22:27] Christy Kesslering, MD: You're gonna open my email every day, my work email, and you're gonna look for these four types of messages, and this is what you're gonna do.” And so we wrote it all down, and that was my, okay, I can breathe and I, you know, I can depend on somebody else for that part of time. Yes.

[00:22:46] Dr: that's what I wanna talk about is because y- you know, for you it was like, “I don't know, this is really, like, seems really radical to do this.” Tell me now that you've done it, now that you fig- and you figured it out, like I loved it, and that, that's why obviously you set it that far out so that you could have this, like, clear space on your schedule and really block it.

[00:23:05] Dr: But now that you've gone through this and you figured out a way to make it happen, what do you think the value of that is? Like, why do you think that that's important?

[00:23:14] Christy Kesslering, MD: Well, I think it was important because, again, what I was initially doing, right, I was looking at how many were coming through and okay, this is still manageable. When I get back, I'm still gonna be able to handle this load of messages, blah, blah, blah. But realizing that every time I saw that number, right, e- even though it was manageable and I said I'm not gonna look, I I was still seeing it and in it.

[00:23:42] Christy Kesslering, MD: And so what we learned is turn off notifications so you don't even know how many have come in, and set a time, right, to go and you look. And

[00:23:53] Dr: why is it important to pull you out of your practice, to pull you out of your life

[00:23:58] Christy Kesslering, MD: Oh, yeah, yeah, yeah.

[00:23:59] Dr: Right? Like, now that you've done it, I'm wondering how you can talk to someone else who's thinking this same thing. Like, well, I know what they're saying, but so why do you think that…

[00:24:09] Dr: What, what, what did you get out of actually

[00:24:12] Dr: putting all of that aside?

[00:24:14] Christy Kesslering, MD: yeah, I think that you, you constantly live even when you don't realize it in fight or flight when you are staying somewhat connected. And so by disconnecting completely, you are disconnecting from your triggers and you are allowing your body to quiet, to, You, you also get a lot of introspection, right? You're in your own head because you're not being distracted by all of these other things. Now granted, I, I wasn't on social media, I wasn't doing those other things, but it took me a number of days to disconnect even from looking at numbers and, and then realizing, oh, I could do this on my pri- my personal email.

[00:24:57] Christy Kesslering, MD: I can do the… Like, oh my God, this is like, I can put my phone, and I was already on like do not disturb, but like taking away notifications, putting myself on do not disturb. And I, and I still use some of those practices today when I am doing things where it's like, you know what, that's not important. I don't want to be distracted in the least little bit. And if I see that, oh, this so-and-so just sent me a text, oh my God, should I go and look at that right now? You know, like nothing is, is an emergency in my world anymore. Not that it really was even before, but there were some radiation oncology things that I had to deal with that were considered emergencies, but not, not many.

[00:25:42] Christy Kesslering, MD: so I just feel like, if we truly want to do the healing, right, we need to put our body into the position that it can best heal, and that is removing all distractions. And so therefore, if you are, you know, a business owner, if you are, like you just really need to remove yourself. And, and again, you can either set up people that can help you do it, but I send out messages ahead of time, like a week in advance saying, “Listen everybody, I'm out, so if you need me, contact me now because then I will not be available, you know, basically for three weeks.

[00:26:20] Christy Kesslering, MD: So I'll see you then.”

[00:26:21] Dr: Yeah. Well, and I think until probably never, other than maybe having a baby, which you can't really call that a vacation, but I remember thinking as a doctor, I'm like, “I'm gonna have a baby, so I can have a little time off.” Like, but other than, right, taking maternity leaves, you've probably never done this where you've really signed out of your business and, like, really unplugged.

[00:26:42] Dr: And I think once you do that

[00:26:45] Christy Kesslering, MD: I didn't even do it during maternity leaves, by the way. I mean, I literally didn't get a maternity… I could have taken one, but that would've delayed my residency, and so I just said, “I'll just take all three of my vacation weeks when I'm, when I deliver.” And literally I had like three weeks off and then people that were very nice and would be like, “Okay, you're good.

[00:27:06] Christy Kesslering, MD: You can go home now,” you know? and then my next one, it was four weeks and then they're like, “Hey, could you just babysit this department for us? And you could bring the baby with you, and you could…” So yeah, I, I had to have numbers three and four to actually get a full maternity leave.

[00:27:23] Dr: So exactly. So the, this when you finally unplug, like in this way that we're doing, is you, you really realize the constant noise that you live in. And until you really make that conscious, and that's why we're so rigid about it, that we say, “No, really, it's, this is not the right fast for you if you're not willing to do that,” because that is part of the healing of getting really quiet within yourself.

[00:27:50] Dr: And, and I remember, um, you know, towards the… It must have been like right when you were starting refeeding, it was like your 14th day and you're like, “Is this crazy? I feel like I could go do like a ab workout or something.” You're like, “I'm ready to…” And it's amazing when you let your body rest, right? And you, you get out of all the noise and you really get quiet, that you felt really pretty good through all of this.

[00:28:20] Dr: Like, I remember that last day where you're like, “I know that I'm gonna go eat because I need to do this. I need to get back to work, but I feel really good.” You felt really good

[00:28:29] Christy Kesslering, MD: Yeah. So, so during my fast, I really never had any hunger, even during refeed, 'cause you were, you warned like, “Oh, some people, as soon as you start refeeding, you get really hungry and don't overdo it. You really need to do this slow.” I was not hungry until my very last day of refeeding, and I went, “Oh yeah, I could actually eat some more right now.”

[00:28:50] Christy Kesslering, MD: You know, so I thought that was super interesting. so the not eating part was super easy for me. I l- I loved, you know, being in my own head. Now maybe that's because I was a swimmer. I spent many a hour in the pool in my own head for years and years and years and years, so I'm always good being in silence and doing quiet activities.

[00:29:11] Christy Kesslering, MD: but my detox, right? So like, what? Day four to nine, I had pretty decent low back pain and, and one or two days so bad that I couldn't even sleep at night. I– we were joking that I was, like, pregnant and I couldn't find a comfortable position, and I'm standing, sitting, walking, sitting, laying sideways, doing everything, and I couldn't get comfortable.

[00:29:31] Christy Kesslering, MD: but I could stand, so during the day when I was walking around and standing, like, I just learned don't sit very often. Don't lay down. Just keep kind of being upright, and that helped a lot. And then as that was starting to improve, then my thighs and my buttock, where most women carry a little extra fat, that's my fattiest parts of my body, well, they started aching.

[00:29:56] Christy Kesslering, MD: And I couldn't tell, like, well, is it because of how I was sitting and standing and always putting my arms on my legs or, like, to take the pressure off my back? And then all of a sudden I'm like, oh my God, this is like everywhere I store a lot of fat was tender. Like, I could barely touch my skin. It was so sore.

[00:30:14] Christy Kesslering, MD: And then my skin started erupting. Now I've always had some gut skin issues, which I had pretty much healed, and then this recurred and I'm like, “Oh God, please let the skin go back away when I'm done,” because I'm like, ah, that's just what I need to do is try and heal that again. But anyway, um, pretty, you know, big eruptions on my face and, so it was like all this.

[00:30:36] Christy Kesslering, MD: And then in my labs, which I thought was super interesting, two things stu- kind of stood out to me. I was, I was looking at ferritin levels, and ferritin is an inflammation marker. Now a lot of people in kind of the lay world, you look up high ferritin, it'll say, “Don't eat red meat. Don't eat high iron foods.”

[00:30:54] Christy Kesslering, MD: You know, of course, I was not eating anything, so it wasn't about what I was eating, but my ferritin, like, tripled, quadrupled. I mean, it was up over 400 at one point, and then as I came down through my refeeding and as my detox symptoms are quieting, even though I still had a little bit even still at my six-week point, my ferritin had, you know, slowly walked way back down.

[00:31:20] Christy Kesslering, MD: Still a teeny bit on the high side for me, but much better. And then the other thing I would love to touch on is cholesterol, because we hear that, you know, oh, cholesterol is bad Um, now I didn't run full cholesterol panels, but you might wanna speak to that and we can talk about why. I was just running the HDL ratio only because I have my own custom panels and I have a little bit of a panel that I get a, a minimal discount on for running it.

[00:31:48] Christy Kesslering, MD: And I'm like, “Well, I already have to get these for you. These are the ones that I want. I'll just get those two because if I run this panel, it's about the same anyway, and so it looked at triglyceride and HDL, and we see triglycerides go up, which is not unexpected if we are dumping fat into the system because that is now what we're using as our fuel.

[00:32:10] Christy Kesslering, MD: And then that slowly went, uh, back down and once I was refeeding back way down to where it would normally be. But interestingly, it was the first time I've really seen my HDL in what I would consider a very low range. So it was nice in the 60s and then dropped into the 40s and even into the 30s at one point.[00:32:30]

[00:32:30] Christy Kesslering, MD: And my– what I always tell people is that HDL is your firefighters coming back from the fire. So if your HDL is low, there's a fire somewhere. What is your fire? Well, what was my fire? I was full on detoxing and in pain and, and, and so I'm assuming that that's what it was because as soon as I, you know, came out of that and six weeks later it's right back up into the 60s where I would expect it to be.

[00:32:58] Christy Kesslering, MD: so I thought those two, you know, things were very interesting.

[00:33:02] Dr. Katie Deming: Yeah, and it's one thing, this is important for people to know is that when you're fasting, your triglycerides are definitely going to go up because you're dumping those fatty acids, um, because you're, you know, using those fatty acids to create ketones. So it's normal to see the triglycerides go up, and people get freaked out.

[00:33:21] Dr. Katie Deming: They're like, “Oh my gosh, something's wrong.” But it's like, no, that makes sense. and then the HDL, it makes sense, right, given that you were detoxing at that time, that then the, the HDL's going down while you were, you know, kind of tending with those fires of the detox, and then as you came out of the fast that it came back up.

[00:33:39] Dr. Katie Deming: But the interesting thing that you and I were talking about before we started recording was cholesterol also, like I have clients who are in either Europe or in Australia, and cholesterol panels seem to come with the liver enzymes and, um, kidney function and all of that. just like part of the same panel, I think, um, because I always see it on, on these clients.

[00:34:02] Dr. Katie Deming: And the cholesterol also goes up, and we were talking about what that might be, and I was thinking that maybe it's the same thing with the triglycerides as you're dumping the fat. But you brought up a really good point that I think is interesting. We don't, and we're– just so that people know, we're not saying we know the answer to this question.

[00:34:17] Christy Kesslering, MD: No, no. We are hypothesizing

[00:34:20] Dr: patterns and then hypothesizing m- what might be going on. So do you wanna talk about that a little bit with the cholesterol? ‘Cause I think it's fascinating.

[00:34:26] Christy Kesslering, MD: my bias is that, you know, the LDL-C or the LDL particles are what is carrying the triglycerides to your fat cells. Like, the cholesterol isn't maybe necessarily being stored in the fat cell. Like it's, as Dave Feldman says, it's your boat, right? It is what is carrying things, and then we have kind of a recycling system.

[00:34:48] Christy Kesslering, MD: But we also eat cholesterol, right? So we eat foods that are rich in cholesterol or rich in fatty acids. We're making cholesterol. but what is very interesting is that when we don't eat, our liver will upregulate what it makes.

[00:35:06] Christy Kesslering, MD: And like cholesterol is so important for our immune function. It is so important for our brain health.

[00:35:14] Christy Kesslering, MD: If we are not eating it, our body makes it. And so you'll see this if you do like a blood test for your doctor and you decide, “Oh, I'm not seeing my doctor until 4:00. I don't wanna go back and do the labs that he's gonna order for me when I'm there, so I'll just fast all day, and then I'll go to the lab after I see him, and I'll get my, my cholesterol drawn.”

[00:35:38] Christy Kesslering, MD: And usually LDL and, and total cholesterol will be higher. Again, if you haven't eaten all day, your body starts to upregulate. But when you fast, I mean, I think I've seen numbers in like even up into the very high hundreds, with LDL and total cholesterol.

[00:35:59] Dr: and it may be that the body is making that, as you're saying, because it's so important. And this is the th- you know, it's such a shame. Cholesterol's like gotten just such a bad rap, right? Like,

[00:36:10] Dr: everyone's like, ” My cholesterol's high.” And it's like cholesterol is actually healing.

[00:36:13] Dr: Cholesterol's not the problem. It's the firemen coming to the fire to help. It's like, you know, you see a fire around town, and everyone's like, “Well, the firemen must be causing the fire 'cause every time I see a fire, there's the firemen there,” right? That's like the whole story with cholesterol. So, you know, it's interesting

[00:36:28] Christy Kesslering, MD: So if somebody's, if somebody's going through a big detox too, right? Now they're on pain and they're dumping and they have a huge fire, right? My ferritin went through the roof. My fire, I was on fire. My CRP, which C-reactive protein, which is another inflammation marker, also went up. so I, I, I was on fire.

[00:36:47] Christy Kesslering, MD: So it, it would've been interesting had I drawn LDL and total cholesterol, but my guess is that my LDL went way up because I was on fire.

[00:36:56] Dr: Yeah. And when we say this too, like, 'cause I think some people hear this and they're like, “Well, I have cancer and I don't want any of my inflammatory markers to go up.” But we have to understand that, inflammatory markers are going up because you're doing something really important for your body, which is detoxifying, right?

[00:37:12] Dr: And so you're having this transient increase because we wanna detox the body, but then ultimately that should help with those markers go down. It's kind of… It's funny because my daughter right now, I'm just use this as an example because I think this is just classic in terms of the way people think. So my daughter was exposed, exposed to mold, in a dorm, right?

[00:37:33] Dr: And sh- she's 20 and she's got her whole life and whatever, and her crazy mom, you know, she's like, “You don't know what you're talking about,” right? Even though I talk to all of you guys online. You guys listen to me. You guys know how this is. Your children are not the same. So my 20-year-old daughter's living in this dorm with mold, and like she's describing that has mold, and then she's having these symptoms.

[00:37:51] Dr: She ended up having pneumonia and, like, just not doing well, not feeling well. I'm like, “You need to move out of that dorm so that we can clear you of the mold.” And she's like, “No, I'm just gonna stay through the…” Anyways, long story, she stays through, and then I finally get her tested ‘ cause she had to leave the state 'cause New York is a little tricky with testing, and it was just this whole thing.

[00:38:10] Dr: Finally get her tested. Of course, her levels are off the chart, so then I, I'm giving her something to detox. But she's like, ” Mom, I feel horrible. I can't take this stuff and go to work.” And I'm like, “I know you're gonna feel bad while we detox, but if we don't detox, you're never gonna get [00:38:30] that out of your system to get better.”

[00:38:31] Dr: So this is a thing for all of you to remember, is that feeling bad for a little bit and having that fire, you know, as Dr. K. is talking about, is part of the process of healing, and you're gonna have this inflammation. But then once you get rid of it, you've detoxed those, you know, things out of your system, and so the temporary inflammation is the cost that you're paying for the long-term clean- you know, cleaning out of your body, you know?

[00:39:00] Dr: ‘Cause I think sometimes people hear that and then they freak out and they're like, “Oh, well, I definitely don't wanna fast then because I'm gonna have inflammation.” It's like, yeah, but you got inflammation in your body all the time because you've got those toxins just hanging out all the time.

[00:39:11] Christy Kesslering, MD: Well, I, you know, you, you could liken it to, you know, you brought up mold, right? How do you remediate a house? You've– you have to make it look a lot worse before you can clean it up, right? It's like remodeling your kitchen. It looks like chaos, but then when it's all put back together, it's bright and shiny and beautiful.

[00:39:33] Christy Kesslering, MD: So, so w- we'll always see maybe some… It's, and it's why even when you first start fasting or start a ketogenic diet and they call it keto flu, right? You're switching meta- metabolism. Like you, some people will feel worse. In fact, who was I talking to? Somebody was saying, “Oh, I didn't understand it,” but you know how you can get like, they talk about keto adaption.

[00:39:59] Christy Kesslering, MD: Even though you're following a ketogenic diet and you're making ketones, maybe I'm not very good at burning them, and that's why I have this ketone breath or, or the, the sweet smell under my armpits, or maybe I'm getting a rash because I'm getting rid of ketones in other ways, urine, breath, sweat. and he was saying it took him a year and a half before he didn't have that

[00:40:23] Dr: Yeah.

[00:40:25] Christy Kesslering, MD: you know? So again, there's a lot of work that often needs to be done before you really are finding, finding the sweet spot.

[00:40:34] Dr. Katie Deming: And actually, I just had a fa- a client who fasted for, he did 25 days, and he said the same thing, that he was on a ketogenic diet for a good 18 months to two years before his body really became adapted, which so interesting

[00:40:50] Christy Kesslering, MD: and even then, we're constantly in different situations and different stressors. So as I will always say, there is no, like, steady state. You're constantly– I, I always use the analogy that you're on the log ride and you're constantly bumping up against the sides. You just wanna keep redirecting yourself down the sh- center,

[00:41:10] Dr. Katie Deming: Yeah. Yeah, beautiful. And then let's talk about your talks, like your talks because I think that's really actually, valuable in this conversation about what did you see? And I know,just for a refresher for everyone that she, Christie tested, I think it was back, was it 2024? ‘Cause it was a

[00:41:27] Christy Kesslering, MD: So it was long. With the toxin panel, the, the most recent one I had was 2023. I didn't even think about doing that. We were so kind of focused on this muscle mass, so I knew I was gonna do the DEXA scan. I knew I wanted to do labs. I didn't really think about doing any of the specialty tests until I was dumping toxins, and I'm like, “Oh, I wish I would've done a toxin panel right before,” because I did do one at the six-week mark post.

[00:41:57] Christy Kesslering, MD: But I, I kind of went back and looked at my history because I had two in 2020, then I had one in 2023, and then I had this one in 2026. And I had a number of, toxins that were present back in 2020. I had done some work initially just saying, “Okay, I'm just gonna do this little bit. Does that help?” And it was actually moving some things.

[00:42:21] Christy Kesslering, MD: and then I started to incorporate sauna and additional binders and just the continued, you know, optimal diet, but then I've been following that for, uh, like ever. but anyway, I, I just kind of cleaned it up a little bit more, a little bit more. Really got into the environmental toxin i- world of switching out products and cleaning waters and all of that.

[00:42:43] Christy Kesslering, MD: Like, that was a new thing to me back in 2020. so slowly incorporating lots of those things, but there were a couple things that stayed still in the very, very red, area. So they give you a green, yellow, red, and again, who, who sets those? I don't know. But, pretty much every year I still had some red.

[00:43:06] Christy Kesslering, MD: and this most recent one, I had some that were, like, at the top of the red, like uber high high. So if I give you… I'll give you one example. Uh, one was butylparaben, which I'm convinced actually was something maybe at work. So maybe leaving work in 2021, end of 2021 helped, but again, in 2023 it really wasn't that different.

[00:43:32] Christy Kesslering, MD: So I went from like 20, 25, I think I was still at, uh, uh, still at 25, then I went down to 25, then I went down to 24, and then I went down to .8 after the fast.

[00:43:43] Dr. Katie Deming: Mm-hmm.

[00:43:44] Christy Kesslering, MD: So that was a pretty dramatic drop, and then there was another phthalate that was high but had been walking down, so each year it got a little bit lower, but it was getting lower by like Maybe 50%.

[00:43:58] Christy Kesslering, MD: And, and it went from like 1,800 to 900 to green, not even detectable essentially. So I'm like, “Holy smoke.” So there, there were a number, so now I have zero reds. I have, a few, you know, yellows, but that are pretty moderate to low end of the yellow, and everything else is green. And so I, I thought, “Wow, that…”

[00:44:25] Christy Kesslering, MD: Again, that's what I was feeling in my body while I was going through it, so I feel like that was reflective of that. again, I don't have great data before, so it's hard to say exactly what was fast related and what was just my constant continued attention to those things. But I thought that was pretty powerful still.

[00:44:45] Dr: Yeah. And then how about other metrics? So I know that you were checking insulin through this. Like, what did your insulin do? ‘Cause I think this is one factor that a lot of people are interested in, is like what happens with their insulin through fasting,

[00:44:58] Christy Kesslering, MD: So I only have a few time points. I, I– in retrospect, I wish I would've done a couple more. So I was– I did one pre, I did one at one week, one at two weeks, which was the end of the fast, and then I did one mid refeeding, one after refeeding. But what I noticed is, again, if you're comparing it to ketones, 'cause this is what I understand from the literature, is that your ketones will climb to a point,

[00:45:25] Christy Kesslering, MD: and then your ketones will level off or even drop.

[00:45:29] Christy Kesslering, MD: And the rationale that I've, you know, again, this is my, my knowledge base, maybe not right, I don't know. But, but basically we're dumping fat, we're creating ketones, and then our body says, “Hey, you know, I've got plenty of ketones. Could you maybe like dial down that fat dump?” And what holds fat in the cells but insulin?

[00:45:50] Christy Kesslering, MD: So my insulin was up just around the time, again, probably a few days earlier, but, but according to when my ketones started dropping, my insulin is higher. Pretty dr- you know, in my world, dramatically higher. In the conventional world, normal, looks great. Um, and then, once I started refeeding, then it started walking right back down.

[00:46:17] Christy Kesslering, MD: So during my fast, I almost look insulin resistant. But my, my bias, again, as to what happens when we block fat, so now our body says, “Hey, you've got enough ketones, so stop dumping fat.” But we still need fuel. We still, we still need nutrients, and that's my bias, my belief, is that is when we go into autophagy.

[00:46:45] Christy Kesslering, MD: And that is when our body says, “Hey, so instead of like dumping more fat and raising these ketones, what if we just start recycling dead cells, damaged cells, cancer cells?” So my bias is insulin going up a fast is actually a sign of when autophagy kicks in. But that's not the same thing, 'cause there is data that if you take exogenous ketones and you jack your ketones up, that a similar thing happens, that insulin goes up.

[00:47:17] Christy Kesslering, MD: But I don't think that's the same since you're already bringing in food and adding exogenous. Like, what is the need to break down cells? So just being in deep ketosis does not equal autophagy.

[00:47:31] Dr. Katie Deming: Yeah, so the, result of adding exogenous ketones to get these very high levels of ketones versus the high levels of ketones that come with fasting and then insulin rises with each of those, the potential benefits are different because when you're in a fed state and you're just adding exogenous ketones, you're not in autophagy, right?

[00:47:52] Dr. Katie Deming: But in a fasted state, when you get to that point, that's a sign that actually the body is now preferentially looking for other tissue to recycle as part of the healing. So, yeah. And then your insulin levels w- came down after the fast, right? So that was just a temporary, and then they came down and they were lower bef- after the fast than they were before the fast.

[00:48:12] Dr. Katie Deming: Slightly?

[00:48:14] Christy Kesslering, MD: yes, but not, not actually where I normally am, 'cause remember I was doing some experimentation right before. So, so it came right back down to about where I normally sit

[00:48:22] Dr: Which had been at a healthy level for you, so yeah.

[00:48:25] Christy Kesslering, MD: Right

[00:48:25] Dr. Katie Deming: That's perfect. are there any other labs that you want to call attention to that you think would be helpful to just talk people through? I know we've covered quite a bit.

[00:48:34] Christy Kesslering, MD: Yeah, I don't think that there was anything… The only other thing that went up a little bit were those liver markers. So again, AST and ALT were the only two. I don't think I was even looking at GGT. but those,did tick up a little bit during the right? You're asking your liver to do more work, and as soon as those symptoms were going away, right back down into a normal, what I would consider healthy.

[00:49:02] Christy Kesslering, MD: Now granted, all of those were considered healthy by your conventional doctor, but I'm looking at

[00:49:08] Dr. Katie Deming: The tr- you were looking at the trend, and that's, that's a common thing that we see is liver enzymes going up while your body is detoxing, and then they come down, usually normalized by, six weeks after the fast if they did go out of range. So perfect. Well, Chrissy, honestly, it was a privilege to have you come in and do the fast with me because it's always exciting for me to have, like, a colleague in where you know the numbers, and so, it just was, like, really fun to have you in there, and then also with all the data that you've pulled after from testing before and after, for me, I love it because it just gives us more information.

[00:49:46] Dr. Katie Deming: There aren't a lot of people who are doing this for the reasons that you said is, like, people are afraid of prolonged fasting 'cause they think, you know, your protein or, uh, lean body mass and all of that stuff. So as we're doing it, having someone who's tracked themselves so closely is really helpful for me, um, and it's just been a privilege to spend that time with you, and also we share lots of clients back and forth too, which has been a privilege.

[00:50:08] Dr. Katie Deming: tell people how they can find you because I, I love the work that you do, and I just wanna put a plug in for you. I know that you're booked and, like, crazy full. You're not looking for more people necessarily, but what you and I have s- It's so interesting 'cause I feel like we're in some ways the same people.

[00:50:24] Dr. Katie Deming: Like, we both, like, we're swimmers and divers and radiation oncologists and then now left the system and, and have this, like, kindred relationship, but then our practices are actually very complementary, right? Like, I'm doing the fasting, the emotional work, kind of that deep, deep reset, and then you're doing the tracking for people, you know, and both before and after the fast and, and that kind of thing.

[00:50:45] Dr. Katie Deming: But tell people what your practice is about and how they can find you.

[00:50:49] Christy Kesslering, MD: So the easy part is how to find me, kesarex.com. on that I do, there's a schedule so you can book appointments directly. From there you do get an idea of, in the frequently asked questions, like what do I do? But basically, for every new client, I'm really trying to get a broad set of labs so that I'm looking at insulin and IGF-1, and I'm running insulin resistance calculations.

[00:51:16] Christy Kesslering, MD: So I'm not just, again, looking at your glucose and your hemoglobin A1C, which are very poor markers of metabolic health. they only show you when you've got a really bad problem. They don't show you, you know, that you have a brewing problem. I look at all these inflammation markers. I look at nutrient markers, nutrient status.

[00:51:36] Christy Kesslering, MD: So I'm really trying to help people look under the hood and say what things are out of balance, what thing… And I, and I can't say that this is due to X or this is due to Y. I can say that these are the likely culprits, like what thing maybe is your issue, or let's try this and see which markers move, and then if certain ones aren't moving the way we would expect, what other layers do we need to look?

[00:52:04] Christy Kesslering, MD: What other rocks do we need to lift up? Um, and, Yes, I am booking out, but for new clients, but I do my best to move people up. I'm always having people reschedule. I don't like running labs if people were just sick, you know, and they, “Oh, I just…” Or, “I just got back from, you know, an international trip, and should I get my labs tomorrow?”

[00:52:26] Christy Kesslering, MD: Like, no, let's reset. Get back on your actual normal circadian, like get back onto your time zone. I don't want jet lag. I don't want your travel. I don't want the water retention or whatever. So let's… So then I'm always rescheduling, and I just want someone ready to go. So I need somebody who's already done their paperwork and have already done the labs for me, and they're ready to go, and I move them up.

[00:52:48] Christy Kesslering, MD: So almost nobody waits to their appointment time unless they want to wait until… So some of your clients, we need to wait six weeks post-fast before I run these labs, so let's, let's wait. And, and I'm happy to meet with folks, so there are some appointments that I can squeeze in very readily if someone just wants to do a discovery call and talk to me and meet with me.

[00:53:09] Christy Kesslering, MD: Others wanna do kind of a p- what I call a pre-consultation, meaning we're not gonna look at labs yet, but somebody who needs to make like, “Okay, they're telling me I need to do surgery tomorrow,” or, “I need radiation. Like, could you just advise me on that while we're waiting for the next step?” And so those are appointments that I can usually move up to within a week or two.

[00:53:30] Christy Kesslering, MD: So I try not to make people wait too long, but it does depend on my client load. And I have learned through Dr. Deming that there is a nice work-life balance that we need to, you know, set for ourselves. It makes me a happier person. It makes me work with you better, because if I'm, again, with a client, it, it's like if, if I'm drained, I have nothing to give to you,

[00:53:52] Dr: Yeah. Absolutely. Yep, you gotta fill the tank before you can give anything to anyone else. So I love that, I love that you learned that. well, thank you so much for joining me. It's been really a, a joy to talk to you about this and share it, and I think that people find a lot of value, in the information you shared today.

[00:54:09] Dr: So thank you so much for being with us

[00:54:11] Christy Kesslering, MD: You're so welcome. Thanks for having me

[00:54:12] Dr. Katie Deming: If there's one thing I hope you carry out of today's conversation, it's that your body is far more capable and far more intelligent than the fear stories give it credit for.

[00:54:23] Dr. Katie Deming: To summarize what we covered today, here are the key points. First, \muscle fear that so many people carry into fasting is not accurate. Christy came in with before and after scans, and after her 14-day water fast, her body fat went down while her lean body mass actually went up. That is the opposite of what we're warned will happen and the opposite of what crash dieting does to the body.

[00:54:51] Dr. Katie Deming: Second, the discomfort that showed up around day four, the back pain, the skin, the toxin markers moving, that wasn't something going wrong. That was her body doing the deep work of clearing out what it had been carrying for years and then settling back down as she came through it. And third, that rise in her insulin in the middle of the fast and the process Christy believes is, was pointing to was her body shifting from simply burning fat into autophagy or recycling what is no longer needed.

[00:55:23] Dr. Katie Deming: It's her hypothesis, and it's a fascinating window into how much is happening beneath the surface when you give the body room to do its work. Thank you so much for listening. I know your time and attention are valuable, and I'm very grateful that you chose to spend time with me today.

[00:55:40] Dr. Katie Deming: If you're not sure whether prolonged fasting is even the right kind of fasting for where you are right now, I created a short quiz to help you figure that out.

[00:55:50] Dr. Katie Deming: It's called Which Fast Is Right For You, and it points you toward the approach that actually fits your body and your situation. You'll find the link below. One honest word before you go. Prolonged fasting at this depth isn't as simple as just not eating. There's real preparation that goes into it, a lot to consider along the way, and refeeding matters as much as the fast itself, which is exactly why this is something to do with guidance, not to improvise on your own.

[00:56:21] Dr. Katie Deming: Your body is the authority here, and this episode is for education, not a protocol for your specific situation. Thank you for listening, and remember, just like me, you were born to heal.