Subscribe
Share
Share
Embed
Save 20% on all Nuzest Products WORLDWIDE with the code MIKKIPEDIA at www.nuzest.co.nz, www.nuzest.com.au or www.nuzest.com
Curranz Supplement: Use code MIKKIPEDIA to get 20% off your first order - go to www.curranz.co.nz or www.curranz.co.uk to order yours
Curranz Supplement: Use code MIKKIPEDIA to get 20% off your first order - go to www.curranz.co.nz or www.curranz.co.uk to order yours
This week on the podcast Mikki speaks to Dr Krista Varady, a leading researcher in the field of intermittent fasting and metabolic health. With a wealth of publications to her name, Dr. Varady is best known for her pioneering studies on alternate-day fasting and time-restricted eating. Her research has been instrumental in advancing our understanding of how intermittent fasting can impact weight loss, metabolic markers, and overall health.
In our conversation, we delve into the science behind intermittent fasting, uncover some of the myths and misconceptions, and discuss the latest findings from her groundbreaking research and how they translate into the real world experience.
Dr. Krista Varady is a professor of nutrition at the University of Illinois at Chicago and a leading expert in the field of intermittent fasting. Her groundbreaking research focuses on the effects of various fasting protocols, including alternate-day fasting and time-restricted eating, on weight loss, metabolic health, and disease prevention. With over 100 peer-reviewed publications, Dr. Varady's work has been instrumental in shaping our understanding of how intermittent fasting can be used as an effective tool for improving health outcomes.
In addition to her research, Dr. Varady is the author of books for the general public including 'The Every-Other-Day Diet,' and ‘The Fastest Diet’ where she offers practical advice on how to implement fasting protocols for long-term success. Her work has been featured in numerous scientific journals and popular media, making her a trusted voice in the nutrition science community.
Dr Varady can be found here https://ahs.uic.edu/kinesiology-nutrition/directory/varady-krista/
Her books: https://www.amazon.com/Every-Other-Day-Diet-That-Lets-Weight/dp/1401324932 and https://www.amazon.com/Fastest-Diet-Supercharge-intermittent-fasting-ebook/dp/B0CHTM7653
Her paper discussed here: https://www.nature.com/articles/s41574-024-01009-4
Creators & Guests
What is Mikkipedia?
Mikkipedia is an exploration in all things health, well being, fitness, food and nutrition. I sit down with scientists, doctors, professors, practitioners and people who have a wealth of experience and have a conversation that takes a deep dive into their area of expertise. I love translating science into a language that people understand, so while some of the conversations will be pretty in-depth, you will come away with some practical tips that can be instigated into your everyday life. I hope you enjoy the show!
Transcribed using AI transcription, errors may occur. Contact mikki for clarification
00:00
Hey everyone, it's Mikki here, you're listening to Mikkipedia and this week on the podcast I speak to Dr Krista Varaday. Dr Krista is a leading researcher in the field of Intimidal Fasting and Metabolic Health. With a wealth of publications to her name, Dr Varaday is best known for her pioneering studies on alternate day fasting and time-restricted eating.
00:26
Her research has been instrumental in advancing our understanding of how intermittent fasting can impact weight loss, metabolic markers and overall health. In our conversation today, we delve into the science behind intermittent fasting, uncover some of the myths and misconceptions, and discuss the latest findings from her groundbreaking research and how they translate into the real world experience. So Dr. Krista Varaday is a professor in nutrition at the University of Illinois at Chicago.
00:55
and a leading expert in the field of intermittent fasting. Her research focuses on the effects of various fasting protocols, including alternate day fasting and time restricted eating, and how these impact on weight loss, metabolic health and disease prevention. With over 100 peer reviewed publications, Dr. Verde's work has been instrumental in shaping our understanding of how intermittent fasting can be used as an effective tool for improving health outcomes.
01:21
In addition to her research, Dr. Veraday is the author of books for the general public as well, including the Every Other Day Diet and the Fastest Diet, where she offers practical advice on how to implement fasting protocols for long-term success. Her work has been featured in a number of scientific journals and popular media, making her a trusted voice in the nutrition science community. And Dr. Veraday is just another example of
01:47
a scientist that really can bridge the gap between what she does in the laboratories in her university job and what we understand in the public, which is why I was so thrilled to have this conversation with Krista. I have put links as to where you can find Dr. Varaday in the show notes and I've also put links to her books and the paper that we discussed predominantly around the myths and misconceptions of intermittent fasting that is all in the show notes.
02:16
Before we crack on into the episode though, I would just like to remind you that the best way to support this podcast is to hit subscribe on your favorite podcast listening platform. That increases the visibility of Micopedia and amongst literally thousands of other podcasts out there. So more people get the opportunity to listen to guests that I have on the show, including Dr. Christa Varaday. All right, team, enjoy this conversation.
02:44
Esther, thank you so much for taking time to speak to me this morning. In fact, someone who I have also recently interviewed, Tony Butajie, I think I want to say his name. He was the one that, yeah, he got me onto your research actually, because we are all quite interested just in the same, I suppose, area on looking at intermittent fasting and its impacts on health and in some of the potential differences. But also, of course, the myths, which is something which I hope to talk to you about.
03:14
today also. Can we kick off, how did your, could you give us just a little bit of your background and how you became interested in alternate day fasting, but also of course time restricted eating? Yeah, so I've been studying intermittent fasting for about 20 years and our lab has probably done most of, the most human trials in this area to date.
03:37
So I started out studying alternate day fasting, but then seven years ago or so, I shifted gears to time restricted eating because I noticed that alternate day fasting was kind of tough and people weren't actually doing it. Oh, that's actually a really good point because I suppose one of my questions for you was, how feasible it might be for someone to do alternate day fasting. And I mean, you've literally just answered that. People just didn't adhere.
04:05
Alternate day fasting is that kind of fasting where you have to do 500 calories one day and then you get the next day where you can just eat whatever you want. So I started studying this because I thought it would be easier to do than daily calorie counting because you kind of get that day off of dieting every other day. And then I realized that, yeah, eating 500 calories one day is really tough and we would get like 40% dropout rates when we ran those.
04:32
alternate day fasting studies. So now I pretty much exclusively test time restricted eating. Yeah, interesting. Do you think though, Krista, like, because I think about those models with alternate day fasting and think, you know, well, you do have, it's, I suppose it's the 500 calories makes it, is, I guess, is that the magic number? Or if you looked across a week and you achieved a, you know, significant calorie deficit, like,
05:01
Would there be too many differences in terms of some of those health improvements that people might get? Yeah, that's a great question. So I, having studied this for so long, I think that all the health benefits of intermittent fasting are just from the weight loss and calorie restriction. I don't think with like time restricted eating or even alternate day fasting, I don't think we're undergoing a long enough period of time where we're not eating.
05:26
to get any of the ketone or autophagy benefits that you would get. I think all intermittent fasting does is it helps people eat less, and then that results in usually three to 5% body weight reductions over anywhere from two to six months. And then because of that, you get the downstream effect of lowering cholesterol and blood pressure and that type of improving glycemic control. But I don't think there's anything magical about the diet.
05:54
it doesn't work any differently than calorie restriction. Whenever we compare them directly for alternate day fasting and time restricted eating, we've done the longest studies in that area for over a year. They, yeah, there's no differences between the calorie restriction and fasting groups for any parameter. Yeah, it's so interesting because what, see with everything that you've just said, it does make me wonder why the whole concept of time restricted eating or intermittent fasting gets such a bad rap.
06:24
when ultimately for, and I guess this is what we'll talk about, like in the majority of populations we're only seeing positive outcomes. Or have I just put those words into your mouth? No, I completely agree with you. I think, well in America, like not speaking from like obviously a New Zealand or Australia's perspective or anything like that. I just think that...
06:48
Americans were really against it at first because just the concept of not eating was kind of anti-American. It's like, what, you're going to take our food away, Nat? It's just like, how dare you? So I think people had a lot of issues with it from that perspective. So I started studying this in the mid-2000s. And people would, when I would give talks at scientific conferences, people would walk out and be like, you're starving people. You're going to give people eating disorders.
07:14
But now that a lot of people are doing it, and it's popular on social media, so people can kind of see the benefits people are getting, I think there's a lot more acceptance around the diets. There's still myths, and that's why we wrote that, Debunking the Myths of Fasting, Paper and Nature Reviews a couple months ago, just to kind of tackle the major myths that are still out there that are not based on science at all.
07:40
Yeah. Okay. And can we just jump to that paper actually? And I'll link it for people in the show notes because I feel like there is like the myths around time restricted eating, it's almost in both directions. Like I just mentioned that it gets a bad rep because people, you know, think it's harmful for some of the reasons that you've described. But then of course, you've got people on the other side of the fence who are like, this is, there's something uniquely different about time restricted eating over and above the calorie restriction. So,
08:09
I know that you might mention all of those in your paper. So can we just sort of go through those major, I guess, sections of your paper to, I guess, dispel the myths? Sure. Yeah, no problem. So I'd say the main myth that's still kind of lurking out there is that intermittent fasting ruins people's sex hormone levels or causes estrogen and testosterone to go down.
08:33
But that's not true. So whenever we've measured that over a year with time restricted eating and we found basically no changes and that's a paper we also just published that this year. So we don't see any changes in sex hormones in premenopausal women, postmenopausal women, or in men. So no, yeah, there's barely anything that happens. So I think a lot of that came from animal studies. I know one...
08:59
study came out a couple years ago in zebrafish or something. I don't even know what a zebrafish is, honestly. But apparently if you fast a zebrafish, it wreaks havoc on their sex hormones. So then people pick it up in social media and then all of a sudden it's translated to women's estrogen gets tanked and then they can't have babies anymore. It just gets so overblown and no one even recognizes what the initial study was.
09:28
I know that a lot of the concern really came from animal studies, but just to clarify, we're not seeing any negative effects when we run these, when we test this out in humans. I've heard, is that related to Chispeptin? Is that a hormone that I hear time and again that fasting in women reduces Chispeptin and then therefore that's going to decrease estrogen and lead to some of those things? Is that... Oh, that's interesting.
09:56
Yeah, we haven't we didn't measure that we measured all the different types of estrogen like the estrogens, estradiol, etc. progesterone, DHEA. In women, we also measure testosterone, sex hormone binding, glabulins. So a lot of the things that are involved in kind of, you know, menstruation and fertility, but that's interesting. Yeah, we can measure that as well to see if maybe that's that's involved. Yeah, and and
10:23
To be honest, I've tried to do a dive in to see what research is in and around it. I think there may have been one study, it could have been acute. This is what I often see, Krista, just in my reading of it, in many different areas is that you get a mechanism and you don't necessarily think about, well, that's a mechanism. But actually, if you look at the big markers, things that actually do matter, like the things that you're measuring, like actual estrogen production and the different metabolites.
10:51
there's no change. And I wonder how much of some of what we hear is just based on these transient or acute changes and not the long-term stuff that you're looking at. Oh, yeah, that's a really great point. And then also, was it done in humans is the main thing because I honestly don't think that rodent models are good for fasting research because we're finding that almost all of the rodent model studies are not translating to humans just because...
11:19
If you fast a mouse for a day, that's like fasting a human for almost a week. Their resting metabolic rate is very, very high per kilogram of body weight compared to humans. They achieve ketosis within 24 hours, whereas with humans it takes three to five days for the average person to achieve that type of thing. You're really looking at this ramped up version of fasting if you're using that model. In the same way, you do get a lot of really nice benefits in
11:49
But I just don't think, I don't know, whenever people are quoting negative effects, I'm like, can I see the study? And then it's always in like a mouse model or something. And it's like, well, you know, now that we have a lot more human data that came out in the past like five years, we're just realizing that, you know, it's kind of a waste of time and money to measure these like efficacy endpoints and the safety endpoints in rodents. We should be, you know, mechanisms for sure, because you can't like cut out a human's liver or their brain to measure.
12:18
whatever, but to actually look at like, what is the diet doing? And is it beneficial for human health? We should really just rely on the human data now because we have a lot of it. Yeah. Krista, in your studies, are you looking specifically just at that time window and not really focusing on what they eat? It's really just when they eat? Like, how controlled is that in a lot of your research? So we always...
12:43
We really control, we basically like specify that they're eating in an eight hour window. And then we say usually 12 to eight. So we standardize that across all of our trials just because the timing of the length and the timing and the day of the eating window is obviously really important. We do know that right when you wake up, our bodies are like really insulin sensitive. So our ability to kind of put away sugar and deal with nutrients is really good right when we wake up.
13:11
And then over the course of the day, it kind of gets worse and worse. So if you place a window earlier in the morning, you're gonna get better like glycemic benefits. So kind of diabetes risk markers are gonna improve, insulin will probably go down a bit more, insulin resistance if you're eating from like 8 a.m. to 4 p.m. The problem with eating earlier though, is that people just don't wanna stop eating at 4 p.m. So, you know, it is a healthier way to do it. And if people could do it, that'd be great.
13:40
We just, whenever we design our studies, we look at large scale observational studies that, from fasting apps mainly, just showing like what people are actually doing when they do intermittent fasting. And we find that most people do an eight hour window from approximately 12 to eight or like 11 to seven. So that's when most people like to place their window because then they can still engage in social eating. So the dinnertime meal with family or, you know, going out after work for drinks with friends or something like that.
14:09
Yeah. And I guess we, and I think that's what I really love about this type of research is it's translational, right? We're looking at what real people do in the real world and not just when everything is contrived. And I suppose we can't all be like Brian Johnson and have our calories from six to 11, you know? And then that's fine. And in fact, I also wonder about that, because I do have some clients who do practice that early time-restricted eating model, and it really works for them.
14:38
because they're both, like, let's say I've got a couple and they're both doing it in their home and they might also be working remotely. So they're not really, I guess they're less integrated into society than say, the general population who, you know, do have those social sort of like structures to sort of navigate around. Yeah, yeah, exactly. But yeah, just to clarify, we do always standardize that in our studies. And for most of our time restricted eating studies, we do.
15:05
Usually an eight hour window, because that's what people find the easiest to adhere to. And then it also produces clinically significant weight loss of about 5% after six months. And then we've also tested out kind of shorter windows, like four hour and six hour, but we've only done that over the course of like, about two to three months or so, just because I don't know if people could stick to it longer, but I guess we could test that out too.
15:28
Yeah. And what were some of the, were there any key differences if you were to shorten the eating window? Because in practice, I do see this a bit, if people aren't seeing success with a 16-8, generally it's like our human brain is like, oh, gotta do it longer. So did you see any notable benefits or no differences even across that short timeframe? Yeah. So the main difference that we see is that
15:55
shorter windows produce more energy restriction. So if you're eating in an eight hour window, most people just naturally cut out around 300 calories per day without calorie counting. And then if you're eating within a four or six hour window, you actually cut out more calories around 500 calories. So, which, and then because of the greater energy restriction then you get more weight loss. And then with more weight loss, the benefits tend to appear a little quicker. So insulin resistance,
16:24
see that appear more at like, what we saw it appear at like the two month mark with the shorter eating windows, whereas the longer eating windows, usually that didn't happen until I think usually about like three to four months or so when they hit more like 3% weight loss. Yeah, Krista, are those benefits with insulin resistant, they're purely the eating window alone and the participants are not being told what to eat?
16:50
That's right. Yeah. So we, our main instruction is that you, you know, you just fast with energy free beverages during the fasting window. So the 16 hour fasting window. So, you know, coffee, tea, without additives, we do permit diet sodas cause a lot of our studies run for like a year or so. And some people just really want those. So we're, you know, I was trained as a dietitian. So one thing, you know, you can't tell people like not to do stuff cause then they're just going to do it behind your back and not put it in their food records. So.
17:20
And then during the actual eating window, there's no counting calories, which is I think the main reason that this diet has become so popular. I think people just got so sick of tracking, you know, with all the previous diet trends. So like the high, the low-fat diets and then Atkins with carbs and all these things where you're always having to measure your macros or like write down every food you ate in your phone on your like phone app. So with this, it's like.
17:48
you can do, you can basically cut out 500 calories or three to 500 by just like watching the clock and just, you know, starting to eat at 12, eat whatever you want, you know, try to be mindful and eat healthy foods, so less processed foods, more fruits and vegetables, but, you know, after eight just stop eating and just move over to like mainly water and maybe some energy-free like tea, coffee, that type of thing. Yeah, yeah, no, that's, it's such a simplified way for people to
18:17
And you'll appreciate this as a clinician as well, like sometimes just those wins that people get from making initial changes might then spur them to make different diet decisions within that eating window. You know, oh, I'm feeling really good. And then suddenly they're like, oh, I might try going for a walk or, you know, like it can be a real sweet catalyst. Yeah, exactly. Yeah.
18:47
for people who fasted versus those who didn't fast. Do we know of any sex related differences for fasting just as a whole? Like, what can you tell us about that from your research? So we've tried to measure that, like if there's any differences between males and females for efficacy, like body weight and blood pressure, cholesterol, et cetera. But the problem in our studies is that, and in most like weight loss studies, the people that
19:13
turn up for those studies or it's usually like 80% female. So across the board, like not just at our location, it's always predominantly female. So it's really hard statistically then to, if you only have, you know, if you have like 50 women and 10 men, statistically it's really hard to compare the two groups just from the sample size. So it's...
19:38
It is difficult. We've tried to pull things and whenever we pulled our studies, we found that there was no differences between men and women for weight loss or anything like that. Yeah, it's interesting because I think people, in sports science research, there is absolutely an under-representation of females in that field, but actually across public health and weight loss, that's what I've found in my initial research.
20:05
when I was a researcher and then now, if you look at the studies, they're predominantly women. I mean, because women are the ones who predominantly have been interested in weight loss from the get-go. So it's incorrect to say that women across the board aren't represented in weight loss. It's just that sports science research where there's that...
20:29
And then it's also, you know, women, like if we look at it from more of a feminist perspective, like women weren't making any decisions about research until recently. It was predominantly older white men that were deciding where the funding went. And they wanted to exclude women in every respect because of our periods, which kind of messes up a bunch of results because you have to track the first day of the period. So, you know, I think it's disgusting that we didn't even know that women had heart attacks differently until like 15 years ago.
20:57
And now, there's all these different things. But I'd say in lifestyle weight loss intervention research, women now are definitely very well represented. But yeah, in other areas, I think it's still, I think a lot of research will just focus on men, which is unfortunate. Yeah, Krista, so one of the other myths that you discussed in your paper was around excess muscle mass loss. And this is certainly something which, as a clinician, you never want to put
21:27
place people at risk of losing muscle mass because it's such an important sort of marker of health. So can you tell us a little bit about what the research tells us there? Oh sure, so whenever anyone loses weight with any diet, so it could be calorie restriction or the Mediterranean diet, what have you, people, if you lose weight, 75% of that weight loss is fat mass, and then the other 25% is typically on average muscle mass loss.
21:55
So, and again, that happens for every diet. So, and we see the same proportion, the kind of 75 to 25, with all different forms of intermittent fasting as well. And this is measured using a DEXA, which is like a body composition scanner. And then the only way that you can really kind of alter that ratio is if you add protein, like a higher protein diet.
22:19
combined with resistance training, so weightlifting. And those studies have shown that you can actually maintain all your muscle mass, even while you're fasting. But you have to up your protein to usually like 25 to 30% of your calorie needs. That's what I understood as well. So it's nice to see that that's also represented in research. And what about the idea of diet quality? And I guess people just...
22:43
Maybe it's just how our minds work. It's like, oh, we can eat whatever we want as long as we're in this super tight window. So in the research, what do we see with regards to diet quality? So I think our lab is the ones that have measured, kind of compared this the most across the trial and compared to control groups. But what we see is that, well, first of all, people aren't eating super well at baseline, I have to admit. A lot of people eat a lot of processed food.
23:10
fruit and vegetable intake tends to be pretty low. So we do give people very basic dietary counseling in our studies, but we don't want to make it so intense that it kind of confounds the results of our fasting research. So we find that people don't really change what they eat throughout the study. They definitely don't have like worst diet quality from intermittent fasting, but it definitely, it doesn't get better either. So what we see is that it just doesn't change at all.
23:38
So people are basically eating the same foods they ate when they came in the study. They're just eating a lot less of those foods. Yeah. Are there any nutrients we need to be concerned about Krista? Like, do we know that from- Definitely. Yeah. Talk to me about that. I don't even know how to talk about fasting.
23:56
Well, if we look at, I'm sorry, I'm mainly familiar with the American and Haynes data, which is like our diet and our diet here. There's no data in New Zealand, so don't worry. The government is terrible. Yeah, so it's 20 years ago. There's no international health surveys that are done? The last one was done in 2008. Okay. Yeah. All right. Okay, well, then I'll just keep on talking about it. Go for it. It might be similar.
24:26
Yeah, I don't know if the food pyramids are the same, but maybe they are. Pretty much, yeah. I know it's pretty similar to Australia, but... So basically what we see is... I'm so sorry. What was the original question? I just got lost in this thing. Yeah, yeah. No, that's all right. Like any nutrients of concern? Oh, yeah. Yeah. Well, when we look at the NHANES data, which again is the big food surveys we take of Americans, people are definitely low in vitamin D.
24:53
and B12, those tend to be kind of on the lower side. And then, you know, as you age, you definitely need higher amounts of calcium to sustain like adequate bone mass. So I'd say those are kind of the main ones. But you know, really depends, you know, for people that eat more fruits and vegetables, they tend to get a lot more, you know, are just if they more fruits and vegetables are probably consuming also like a higher quality diet. So those individuals probably don't need supplementation. But
25:20
If anybody does want to just take a malty vitamin gummy or something, or calcium and vitamin D while intermittent fasting, it certainly can hurt. So we always say, go ahead. Yeah, nice one. And then what about the idea that restricting the eating window is going to impact someone's relationship with food and create these unhealthy, basically create eating disorders? What does the research tell us about that?
25:46
Yeah, and that's a very important kind of area of research. And I can understand why people would be concerned about that with intermittent fasting. So we, I do have to say, so in all of our studies and in most studies that I've seen, people do, or the researchers exclude people with a history of eating disorders. So people with anorexia, bulimia, or binge eating disorder. I just don't think that these diets are really good for those population groups.
26:13
And then in all of our studies of alternate day fasting and of time restricted eating, we always do these like eating disorder surveys throughout just to see if we're increasing the propensity for someone to develop an eating disorder. And we have not seen that in any of our studies. And this is in like thousands of people at this point. So, but again, these are people that have no documented history of eating disorders. So we're basically just showing that, if you came in healthy and you didn't have
26:42
If you weren't exhibiting those behaviors, you're probably not going to develop them by doing intermittent fasting. Yeah. Okay. Nice one. Krista, I'm interested in any, despite you saying that intermittent fasting is really just calorie restrictions wrapped up differently, are there any differences with regards to, for example, the impact on...
27:09
hormones if someone's going to use time restricted eating versus some sort of continuous energy restriction? Do we know any changes there that might be more favorable or make it a little bit more tolerable for people or otherwise? I used to think that just from some of the early alternate day fasting research, it was kind of saying that alternate day fasting helped people control their hunger a bit more and maybe fullness came on a little quicker with those diets.
27:37
At this point, just looking at meta-analyses, it's the research, it's just kind of all over the place with whether or how these diets affect hunger. I think there's just a lot of inter-individual variability too and how people perceive hunger. And I think people are just measuring appetite wrong because you have to do it in response to a meal challenge. And a lot of the published data out there is just...
28:01
literally giving someone a survey saying, are you hungry? You know, are you full? So to properly, we teamed up with a group from Leeds, Graham Finlayson's group. And he was the one that was like, Krista, you're doing this all wrong. If you want to measure hunger, you have to bring someone in fasted. You have to take their hunger before, give them a meal, which is usually like a standardized meal. And then you measure over the course of two hours what happens to their hunger and their hormones related to appetite.
28:30
So when it's done properly, I haven't seen any differences between calorie restriction and time-restricted eating, but there's very few trials out there. So I think for this, it's kind of still unknown. Yeah. Okay. Nice one. And your work touches on anti-inflammatory effects of intermittent fasting. Do we think that that's sort of specific to... Again, is this...
28:57
literally just the reduction in calories, we think, or is there something about the way that an eating window impacts favorably on some of these inflammatory pathways? Well, with... So obesity is just... When someone has obesity, they have just natural... It's just this low-grade systemic inflammation that happens from obesity, from macrophage and
29:27
So as someone loses weight, typically just again, with any weight loss diet, some inflammatory markers go down, particularly C-reactive protein, CRP, tends to be the most responsive. But we do need like really high amounts of weight loss to see that go down, usually like eight to 10% weight loss, which is a lot for a diet intervention, like with the new GLP-1 weight loss drugs, I'm sure their CRPs are just beautiful at the end of a year or whatever.
29:55
And then in our studies, we've measured TNAP-alpha and IL-6, and we don't see any changes. And then looking again at like meta-analyses that summarize the results of a bunch of studies, it seems that some studies have seen reductions in CRP, but I haven't seen any human trials that found reductions in any of the other kind of inflammatory cytokines. But again, I think it's weight loss dependent. I think...
30:19
Once you achieve close to a 10% weight loss, you might see those markers move then. But just so few studies have seen that amount of weight loss, that's probably why we're not seeing it. And do people's activity levels change in your studies with intermittent fasting? So we recruit people that are previously sedentary or lightly active. So we exclude...
30:44
anyone that's working out all the time, or definitely like athletes. So we're really looking for kind of like a sedentary obese population. And then we have them wear Fitbits or some type of actigraf throughout the whole study and just to measure kind of what they're doing. And we also tell them like, please don't join any, don't start doing a ton of exercise because then that would confound our findings. So we don't see the main measure we use as steps per day.
31:09
and we don't see that change. So most people are doing about six to 7,000 a day at baseline, and then it's pretty much the same. There's no statistically significant differences by the end of the trial. And then for what I've seen from other studies, it's the same thing. Yeah, okay, super interesting. And I feel like part of the bad rep that intermittent fasting gets is just how it is adopted by some of the people that you might exclude from your study, like the super active, the Taipei's, the...
31:37
If I can go and do this, then maybe layer this thing on top of it and probably just go down that sort of too far gone sort of basket. Yeah, yeah, exactly, exactly. So you know, we do encourage them to, you know, like maybe take the stairs instead of taking the elevator, like don't take the stairs instead of the escalator. But we definitely, you know, we say it's fine if you want to join an exercise class or something, but please wait till after the study.
32:07
in with regards to research in this space, be it like, what are you currently sort of doing and what sort of your wishlist? Like what are things that you are really interested in understanding better over the next five years or so? Oh, that's a great question. So we're wrapping up two studies now. I'm kind of looking at like special population groups because we did a lot of our original studies just in like a general population with obesity.
32:34
So we just studied people with type 2 diabetes, and we did one of the first studies in that group and found that it was safe. Time-restricted eating, the eight-hour window was safe in that population. It helped reduce their A1C by almost a full point. After six months, they lost weight, waist circumference, et cetera. And then moving forward, now I'm testing it in people with type 1 diabetes, because it's never been tested. No one has ever, I don't.
33:02
I can understand why now. It's very complicated. You really have to work closely with endocrinologists on that one. But yeah, we just want to see if it's safe because a lot of people would type one and be like, can I do this? And I've always told them, I have no idea because there's no data out there. And then we're also looking more at women's health issues. So we're just about to finish a study in women with polycystic ovary syndrome.
33:29
because that is a syndrome disorder basically or a disease state that has started with like insulin resistance. And one of the main things that intermittent fasting helps out with is lowering insulin resistance. So we're hoping that by lowering insulin resistance in these women that that helps to basically help lower androgen levels, which are higher levels of testosterone in women with PCOS, which can then help them maybe achieve better menstrual
33:58
Um, we have noticed though, in this study that a lot of these are kind of like younger females that have never really struggled with pregnancy, but we've had like five people have to like leave the study due to pregnancy. So that's been, I know I kind of want to ride like libratus supplement or something just because they were like, Oh, I've never, you know, I could, and it's a lot of it I'm sure is the weight loss and you know.
34:21
But yeah, it seems to be working. And so far we're seeing, we haven't done the final analysis, but we are seeing that their hormones are actually being corrected with these diets. So testosterone levels are going down and sex hormone binding levels are going up, which is what are some of the key markers of the disease. That's super interesting. In fact, I was listening to a podcast with someone the other day and they were saying that a lot of their patients who are getting given GLP-1 agonists.
34:49
the same thing. After a couple of months, people are just getting pregnant where they thought that it was impossible. So, yeah, similar things at play, which is super exciting. Yeah, yeah, absolutely. So yeah, special population groups. And then I think one other thing is we might want to... I get a lot of questions about being in the nutrition field. They're like, well, is nutrition important anymore now that we have these amazing weight loss meds?
35:14
We might want to see if time restricted eating can be used as a weight maintenance approach after people maybe discontinue use of those drugs. Because in America, once you are below a certain BMI or body weight threshold, the insurance companies will kick you off the drugs. So maybe we could use that as a weight maintenance approach too. Yeah, after. Oh, that is super smart. That would be a super interesting study to sort of do from the get go.
35:41
put people on the medication and then sort of follow them through however many years you'd need. I don't know. Yeah, yeah, exactly. A little bit interesting. Lovely, Krista. Thank you so much for your time this morning, particularly because, as you mentioned before we kicked off, that you're just getting over cold. So I really appreciate you managing to get here. Can you just share a little bit of where people can find out more about your lab and the research that you're doing?
36:08
Oh sure. So I do have an Instagram page. It's at Dr. Chris severity.com. V A R A D Y is my last name, so hard to spell. We also just published a book in Australia actually. I don't know. So it might be available in New Zealand. It's called The Fastest Diet. And it's me and Victoria Black who published that. And there's a lot of my recent research in that book. And then also it's more of like a how to book on how to do fasting diets.
36:37
That is amazing actually because I think that's, like as I said about, you know, where it can go wrong for people, like there'll be things that people are doing wrong, which should probably just be super easy tweets to enable them to be way more successful, particularly if, you know, because of the research is showing. Yeah, yeah, exactly. Yeah, nice one. Krista, thank you so much. And I'll be sure to put the links to your book and your research and your Instagram page and things in the show notes.
37:07
Oh great, thanks so much for having me, it was really fun.
37:22
Hopefully you really enjoyed the discussion that I had with Dr. Krista. She was super straight to the point, which was awesome. And I think she made it very clear as to what is known in the field of metabolic health and intermittent fasting and weight loss, and what is just potentially conjecture and what we don't know. So that's what I really loved about it. And I can't wait to learn more as she continues to publish her research.
37:49
Next week on the podcast, I speak to Meredith Taranova, registered dietitian and sports nutritionist, ultra endurance running, about nutrition for the ultra runner. And it was a really great conversation, so I can't wait to bring that to you. Until then though, you can catch me over on Instagram, threads and Twitter @mikkiwilliden, Facebook @mikkiwillidenNutrition or
38:16
head to my website, mikkiwilliden.com and sign up to my webinar, Strategies and Solutions for the festive season. That is taking place on Sunday, 17th of November, New Zealand time. It is free and I cannot wait to dive into some of these tools that I use myself and with clients for staying on top of your nutrition as we head into Christmas and summer. That is on my website. We will pop a link in the show notes as well.
38:45
Look forward to seeing you there. Alright guys, have the best week. See you later.