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Satchidananda (Satchin) Panda, PhD discusses the impact of food timing on health, advocating for personalized eating windows and gradual changes to fasting routines. Dr. Panda and Dr. Mindy explore the relationship between fasting, metabolic health, and gut microbes, emphasizing the importance of lifestyle factors like sleep, exercise, and diverse gut microbiota for overall well-being. Dr. Panda shares tips on adjusting to different time zones to support metabolic health during travel, highlighting the holistic approach to health through healthy daily routines.
To view full show notes, more information on our guests, resources mentioned in the episode, discount codes, transcripts, and more, visit https://drmindypelz.com/ep236
Satchidananda (Satchin) Panda, PhD is a Professor at the Salk Institute in California, where his research focuses on the circadian regulation of behavior, physiology, and metabolism in model organisms and in humans. Dr. Panda discovered a blue-light sensing cell type in the retina entrains our master circadian clock, affects mood, and regulates the production of the sleep hormone melatonin. Recently, he discovered that maintaining a daily feeding-fasting cycle – popularly known as time-restricted feeding (TRF) – can prevent and reverse metabolic diseases. Based on a feasibility study in humans, his lab is currently carrying out a smartphone-based study to assess the extent of circadian disruption among adults. Dr. Panda has received the Julie Martin Mid-Career Award in Aging Research, the Dana Foundation Award in Brain and Immune System Imaging, and was a Pew Scholar in the Biomedical Sciences
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Please note our medical disclaimer.
We were taught that doing anything "like a girl" was a weakness. Dr. Mindy Pelz is here to prove it's your greatest strength.
A renowned advocate for women's health, Dr. Mindy is passionately committed to helping women embrace and trust their body's natural healing processes. Drawing on an extensive background in women's health, she's developed groundbreaking, science-backed approaches that help women work with their hormones, not against them, through every stage of life, from cycling to perimenopause to the wisdom of the years beyond.
On Live Like a Girl, Dr. Mindy helps you come home to your own body. Every Monday, she sits down with some of the brightest minds in health and wellness for honest, meaningful conversations that hand you the knowledge, tools, and science to do health your way. No more pushing through, gaslighting yourself, or shrinking to fit. Just permission to live in rhythm with the body you were designed to have and to finally feel at home in it.
Press play, and let's live like a girl.
Dr. Mindy Pelz: On this episode of The Resetter podcast, I bring you Satchin Panda. If you are not
familiar with him, he is the circadian rhythm expert, and has been doing a tremendous amount of
research on time restricted eating, aka intermittent fasting. And so this is a conversation wow that
I have been wanting to bring to you all for a very long time. If you're not familiar with Dr.
Panda's work, I can tell you that not only is he a professor at the Salk Institute in California,
but he has done multiple research studies on circadian rhythm, and particularly how it relates to
the time of food, the time of light, and the time of movement, which we talk a ton about that in
this conversation. He has written two books both all around the circadian rhythm. My favorite one
personally is the circadian code. And he has a really interesting app you all can use and might find
helpful, called on timeout, which is all of his research put together in one area. Now, let me tell
you what you're going to hear in this conversation. So a lot of you have asked me over the years,
when is the best timing of food like Where should I put my eating window? And he's going to answer
that for you. It's really cool. The way he explains it is profound. And right now just so you know,
there's a lot of discussion about like, should I eat when I first get up in the morning, especially
we're hearing this a lot when it comes to protein, that we're supposed to get up and eat protein
right away. He's going to tell you well, I'll give you a little clue. He's going to tell you why
eating immediately upon waking is not a great idea. So you're going to hear that in this episode. I
also want to do bring him into the jetlag conversation, because a lot of people are trying to
overcome jetlag and and figure out how to shorten jetlag. And so I want to know, if you could
manipulate the time of your food to the new timezone you're going to could it possibly minimize your
the amount of jetlag, you have and he answers that really cool. And then of course, we had to go
into the study. So if many of you are still wrestling with the media blitz that happened about a
month ago, talking about 91% increase in cardiovascular health when you intermittent fast, this was
an exact opposition of some of the research he's done on 16, eight fasting, so I wanted his opinion
on what appeared to be the complete opposite of what he's seen in his lab. And then we ended up on
the weight loss drugs, and what does he think about the weight loss drugs and how that fits into
circadian rhythm? And what do we need to know about the up and downside of the weight loss drugs,
really good in depth conversation on all things circadian rhythm. So Dr. SACHIN Panda, enjoy. I hope
so many of your questions get answered in this as it did for me. And I just really deeply
appreciated the way he brings the information forward. So please enjoy. And I hope you get a ton out
of this. Welcome to the resetter podcast. This podcast is all about empowering you to believe in
yourself. Again, if you have a passion for learning, if you're looking to be in control of your
health and take your power back, this is the podcast for you.
Let me start by welcoming you to the Resetter Podcast. And I you know, there's a lot of reasons
people can be a fan of yours. And I really have to say I've been following your research, I've read
your book, I've been listening to your circadian thoughts on timing of food. And it's amazing to me
how much there is to discuss when you just bring up what to eat and when to eat. It's like there's
years of discussion there. And so here's where I'm going to start this is by asking you what's more
important when to eat or what to eat, especially when we're looking at chronic disease and
inflammation and wait
Dr. Panda: wait let is a tough question because it's almost asking you to choose between two, one
out of your two kids. So I guess both are important, but at the same time. Imagine that the good
quality food is your best friend. And that best friend shows up on time When you are free, then
that's good. But if the best friend says up knocks on your door every night at one o'clock in the
morning, then that person might not be that person may not be your best friend. So the point is
timing can make good for junk. So
Dr. Mindy Pelz: that's why, wait, wait, say that again, timing can make good food junk, can it do
the opposite? Can it make junk food good.
Dr. Panda: So I won't say that. It can make the junk food good. But what I can say is it can lessen
the bad effect of junk food, it can lessen the effect of junk food because the timing depending on
what time you're eating, relative to fasting, timing can turn on many defense mechanism in our body,
including genes that detoxify bad things and junk food. So that's why I said that timing can lessen
the bad effect of jobs.
Dr. Mindy Pelz: Right, which doesn't give us a free pass for junk food. I just I just want to point
that out. But it is an interesting, you know, a lot of the research that you've done, I have poured
myself into and one of the conclusions I've come out of your research and really thought deeply
about is if we have such poor quality food, and the food industry is profiting from this poor
quality food, there's no incentive for the food industry to change. So therefore, the best tool we
can give people for again for weight loss and inflammation and metabolic health is okay, just take
that toxic food, and let's compress it into one eating window, so that you have a longer period for
your body to rest. So that like you said, the genes can turn on but it can also heal from the
toxicity of food am I am I thinking that
Dr. Panda: through right through I mean, one caveat, I must say from the beginning is most of the
stuff that I'll be talking about about genes, biochemistry, proteins, or detoxification, all of
these are done in laboratory mouse models, because that's where we can actually go look deeply into
all these factors, we can also give the mice healthy food or junk food at different time of the day.
And very systematically, methodically, we can look at every single gene and the mouse genome. And in
fact, we share almost 99% chance with mouse. So that's why a lot of this can be translated to
humans. In fact, every single medication supplements, everything that we eat, that we take to
madness, prevent or cure any disease were tested. At some point in my so many laboratory animals. So
with that caveat. Most of the biochemical stuff or genetic stuff that I'll talk about mostly comes
from laboratory study, you actually
Dr. Mindy Pelz: bring up a really valid point, because in the world of science, I feel like a lot of
times people will dismiss a good study because it was a mouse study. And they they say, Well, this
is a better study, because it was a human study. And then we have this new emerging question, which
is, but the human studies aren't necessarily being done on on the same demographic, like women
aren't separated out. And I've read some intermittent fasting studies where they had a cohort that
had 17 year old men, all the way up to 55 year old women. And I'm like, You should never look at a
metabolic system of a 17 year old man and compare it to a 55 year old woman. So just for the for the
people listening, do you feel like we need more human studies? Or do you feel like the mouse studies
really are giving us enough information of how to look at some of this behavior for ourselves?
Dr. Panda: Mouse studies give us some clue that it might work in humans, but we have to do the
studies in humans, because ultimately, we're doing all this research not to make myself here,
they're already healthy, but make humans healthier and live a long productive life. So we do have to
go back to humans and do the studies. But at the same time, for example, when I talk about time
retreating or fasting or anything that we do in the lab, and we say what happens in the liver. And
in that case, we're actually going and looking at liver biopsy samples in mice, which would be
almost impossible to do in humans, particularly if you're not having fatty liver disease. And if
your liver is not a threat, nobody's going to give it or give a piece of my liver for simple biopsy.
Yes. Keep that in context like When we're talking about what is the impact of certain things,
medication, or supplements or lifestyle, on internal organs that are very difficult or almost
impossible to sample, for example, we can also look at the impact of timeless refeeding, or
intermittent fasting on brain health. By looking at different parts of the brain, there is no way we
can do that study on humans. But these studies actually tell us, okay, is there enough changes that
we see in laboratory studies to begin to ask this question in humans, because usually, the rule of
thumb is, if it doesn't help a mouse is less likely that it will help a human.
Dr. Mindy Pelz: In other way, I always say it is, animal studies, get us in the ballpark, then we've
got to decide what seat we're gonna sit at. And so I'm a big fan of n of one figuring out how to
take these studies like the ones you're doing, and how do we make them applicable to our own life?
Which leads me to my next major question for you is there's a lot of different lengths of time
restricted eating or fasting that has been researched. Do you have a sense for metabolic health,
again, for cleaning up our metabolic system, which is a huge problem right? Now? What length fast?
Do you feel like does that the best?
Dr. Panda: That's a very loaded question, because it's the one I get all the time. And it's the
let's put it this same way as you're taking medication. So for example, if someone has diabetes, or
pre diabetes, and it's prescribed the medication, commonly prescribed, Metformin, there is no single
dose of medic Metformin that should be applicable to everybody. Because if somebody is newly
diagnosed pre diabetic, maybe somebody should take 500 milligrams of metformin. And if someone
already has diabetes, maybe higher dose, and if somebody has really severe diabetes, then maybe two
or three medications. So we have to put that into context. So similarly, for someone who has
metabolic disease, and when we think metabolic disease, and it's a very fuzzy term, but we can break
it down to individual components. So typically, the three things that affect us that we really are
concerned about are blood glucose, blood, cholesterol, blood pressure, and blood cholesterol, we can
say blood lipids, cholesterol, and triglycerides. Then we can add, say, abdominal obesity, because
that predisposes us to many different diseases. So, so now let's think about obesity, and high blood
pressure, high blood cholesterol, high blood sugar. So depending on who has what, and how severe it
is, that one can have, one can begin with certain amount of fasting. The other thing is, we, when we
are predisposed, or we developed certain metabolic disease, it develops because of our interaction
between genes and our lifestyle. Many of us do have pair jeans, and that's inescapable. But then, in
terms of lifestyle, we have developed our habit of eating certain things, we have a preference for
certain type of for amount of food, it's not that easy to just start fasting right away. So that's
why when we do our studies in humans, first thing we want to see is well, does timing actually, is
timing contributing Miss timing for contributing your disease, or is it something else, like
somebody may be already eating religiously regularly within 10 hours window, but that person may
already have metabolic disease or metabolic syndrome. So there is not much room for improvement in
that case, but paying attention to food quality and quantity might matter. Whereas if someone who is
already eating at a window have slept 14 hours, I'm not saying that every day this person eats
within 14 hours, just imagine and the last two weeks when is the earliest time you add and when is
the last time latest how late to do it. And if that is six o'clock in the morning, some I woke up
and had a cup of coffee with cream and sugar and something else to munch and then the last time I
ate over the last two weeks was going out for dinner and having a very late dinner so at least
couple of times in the last two weeks. They are tonight o'clock 11 o'clock. So that gives me already
1516 hours of window within which my body was expecting food. So in that kiss, reducing that eating
time to a narrow interval might benefit, because
Dr. Mindy Pelz: it's a change what is that because your switch goes from what you're doing
Dr. Panda: habitually are randomly over the last two weeks, if I have eaten two or three times
before 8am In the morning, two or three times after 8pm In the evening. So, that means my body is
already used to expecting for between 7am to 9pm. Vardi has already gotten this signal that Okay, so
this person is likely to eat within such a long window of time, yes, the party remembers it. So in
that case, reducing that timing to a shorter time can be beneficial. So then the question is, well,
can I just go to six hours or two hours or three hours, which will be a huge shock, and people may
not be able to stick to it. So that's why we always suggest, well, if it is too difficult, try one
week within sticking to a 12 hours window that works for you. Depending on what time you wake up,
what time you go to bed and what you do in the morning or evening, try to find the 12 hours that
works for you. It's not saying that you should start skipping breakfast setting from noon to eight
o'clock. But select your own window. And then if if you get used to it for a week or two, then you
can reduce it to 10 hours. Because both mouse studies and human studies that we do, we are saying
that when people who have a habitual or usual eating window of 14 hours or longer so that means over
the last two weeks, you have eaten at least two or three meals. Within that 14 hours Windows suppose
says 6am to 8pm. So that will give you 14 hours, or 8am to 10pm, that will give you 14 hours or
longer than reducing that to 10 hours seems to give many benefits. And so that's the starting point,
they start with 12 hours. And then if you can reduce it to 10 hours, then that's a good thing. Some
people try to reduce event to eight hours or six hours, I must say that we when we look at really
objective data, because we have done this study on many hundreds of people now. And some people say
that they can do eight hours, and they start. And after five or six weeks, we see them drifting
towards 10 hours, and then kind of stabilizing around 10 hours. So that's why we feel like 10 hours
is a magic spot where you can have long term compliance long term adherence. But if you can do eight
hours, that's also good enough. So I think when people reduce it too much, and this is what we have
seen few cases, particularly with women, because when I say not said this, but many women want to
have it all. So they will start intermittent fasting or time to say anything they want to eat within
six to eight hours, they want to improve the quality of food. So they end up eating only solid and
they reduce their nutrient nutrient intake. And yes, and then they go on the go for four miles five
miles run four times, five times a week. And then what happens is your body is actually into a
shock, because the body is not getting enough nutrients and up energy to sustain the basal metabolic
processes that your body needs. And this usually happens mostly with normal weight people are
slightly overweight people were trying to have it all. And if you if women are still menstruating,
then they should, they would see irregular menstrual cycle or some of them can even become M
menarik. And that's a good sign that you are getting into an energy deficit that's not supporting
basal function in your body. That's why we rarely ask people to get to that the eating window to
less than eight hours because there is some risk unless you're paying attention to your quality and
quantity of nutrition and physical activity along with it that can be this pet. So sorry, there was
a very long answer.
Dr. Mindy Pelz: No, that was really well said and actually backs up a lot of my work. And what I've
done with with women specifically is make sure that we don't get at at certain times of the
menstrual cycle too much in this calorie deficit place. And it's specifically around the hormone
progesterone doesn't do well, when we're in too much of a glucose restricted state and the thyroid
doesn't do well with consistent calorie restriction. So I like for women to have more cycling
according to where their hormonal profile is, and what what's going on whether they're menopausal or
menstruating. And it leads me to this question, too, for you is, do you feel like so let's say I
take I go to 12 hours of an eating window, I get comfortable there. Now I go to 10 hours, I'm like,
hey, 10 hours is good. I think I'll just stay here. Do you find that the fasting benefits stop? What
if you are just super comfortable with 10 hours and you just do 10 hours over and over and over and
over again? Will you eventually plateau with results? Does the healing stop? What do we know about
that? Yeah,
Dr. Panda: so there are very few long term study of a year or more. So it's very difficult to say,
what are the benefits, but what we see is you got to define what are the four are the benefits
people experience. So when we ask people why they continue to do it, what is driving them to do it
than that usual response is actually not metabolic health to be as the immediate benefit, what they
say is the some of them that said that the sleep better, particularly those who stopped that eating
window, at least three hours before the habitual bedtime. So suppose say, if you're going to bed at
10 o'clock, if your kitchen closes at 630 or seven, then that tend to sleep better. And when and
then they experienced that if they eat later at night, and that night, they have bad sleep, or they
wake up in the middle of the night. So they tend to do it because the sleep better. The second
benefit that we always hear is I think that's to sleeping better, is that feel more energetic
throughout the day? And yeah, you know, if you're eating late and slipping back, then of course,
you'll feel lethargic the next day. So this is another benefit. And then the third one is, a lot of
people who have acid reflux or heartburn, either disappear to have acid reflux or heartburn goes
down, or some of them who have mild form, it may disappear altogether. And these are the things that
actually drive people to stay with it. Then the question is, yeah, well, suppose that somebody was
pre diabetic, where the blood sugar level was fasting blood sugar level was between 100 to one and
qualify, they started doing intermittent fasting or timeless eating so within 10 hours, and that
became normal glycemic. And then the question is, if they continue to do this, will they again
become pre diabetic? Because that's when he will sell and while the benefits kind of disappear, and
this is meant, personally, I haven't seen any case where people enter they said, there are not too
many studies where the studies have continued beyond one year. There is no theory study beyond one
year, but what I hear anecdotally from people and also in my own family, one or two people who who
are pre diabetic that became normal, glycemic, the benefits continue for 567 years now. And then the
weird thing is, once they start eating outside that window late in the night, then yes, they
haemoglobin AirWatch, they go off slightly, the fasting blood glucose go up, and then they see that
and then they come back, reattached to this 10 hours, window, eight hours window, yes. And then
they're still within the dance. But the point is, as we get older, our risk for many of the disease
also goes up. So it'll be interesting to see after 567 years or 10 years, we lose again become pre
diabetic, or will their blood pressure go up slightly, because if there is a genetic condition than
the lifestyle, they'll show up. Yeah, same time, you know, yeah, interesting. The point is,
particularly the ages between 35 and 60. That's when of course I don't want to say that 35 is middle
lies, but it's three middle lies.
Dr. Mindy Pelz: Oh my gosh, you just you just made a few people turn off from
Dr. Panda: but this video is very crucial for all of our lives because we want to be at our optimum
physical, emotional and intellectual help. Right? The physical health we have to be metabolically
healthy, we should be free of any disease for which we have to take Can medication every single day,
let's put it make it very clear that because this is the time when we have other things to do, this
is the time when people start a family, or those who started a family earlier, this is the window in
which the kids will get out of the house, they'll go to call us. When you're talking about 50, to
60, maybe if you had kids earlier, you may even become a grandparent. This is also the time when
there are a lot of life changes are happening, you may be changing, changing jobs, or maybe going
for the no personal life. Also, some people may or may get out of a marriage get into another
relationship safe. This is also the time when people get into double or triple caregiving, the
parents are aging, we have to give them care, the kids have not fully grown up yet here to care for
them. And then if your spouse or your loved one has some other condition, you have to care for them,
you have lot of responsibilities at home, at work, you may be having some community and guest man,
other stuff outside your friend family relationship, then your friendship a lot of things go on
during this as from 35 to 60. So that's why it's very critical to maintain optimum physical,
emotional and intellectual health. In those years, and once you Yeah, men 10. Once you glide to fly
to the age of 60, with great health, emotional, intellectual and physical health, then the rest of
the life the next 30 years or 40 years will be much better. So that's why Oh,
Dr. Mindy Pelz: amazing. I only have four more years to go. So you want to hit 60. In the best
metabolic health possible is that what you're saying? You're amazing.
Dr. Panda: I want to say that I have a personal goal that depending on how you look at it, if you
have children then have a personal goal that use it be metabolically healthy without any chronic
medication. When your kids finish high school, or kids finish college, or when your kids are getting
married so that you can actually dance real dance, not the slow moving. Dancer, like I was asking
somebody, why do you want to be healthy? And the person said that I want to be elite dance and my
daughter's wedding. Yeah. Reason that's a really that's what matters. So that's why coming back to
the security and like that, what happens is when you think about lifestyle, lifestyle breaks down to
nine components, that is the quality, quantity and timing of food, exercise and sleep. And once we
take care of this, at least if we take care of the timing component, then everything else falls into
its right place. Because to be very clear, it's very difficult to remember, even keep track of how
many kilocalories we eat in a day. I don't know about you, nobody can sustain. I cannot guesstimate
how many kilocalories I have consumed now. So yes, and the quality also, I cannot say how much
carbohydrate protein or fat I consume on any given day. So yeah, the only thing I remember is the
timing. So that's why timing becomes a very tangible, very possible aspect of her life. And just
imagine everything that we do in a day even this conversation that we have between you and I we set
a time and we did it and once we are on time, then everything flows perfectly fine. Just imagine if
I was half an hour lens podcast, you'd be so upset and math.
Dr. Mindy Pelz: Everything Off. It's a good analogy. It's a really good
Dr. Panda: family. A body has the circadian timing so that means it has a timetable. That tells us
that has already pre planned that has already prescribed us. I ideally when we should go to bed, how
long we should be in bed, when we should wake up when we should start eating when we should stop
eating one is better for us to go out there and do some exercise and one to one and if we are on
that tie. If we are on time with our body's circadian schedule, then everything will fall into its
right place.
Dr. Mindy Pelz: And amazing so well said. So, when we're looking at the timing of food is this has
been a question my community has asked over and over again, when's the best time for me to eat? Is
it I always say eat in the daylight, we have some new research that's coming out saying you should
have protein within a half an hour of waking up in the morning. We have other people say, you know,
wait a couple of hours after you wake up. And yet I think a lot of fasters skip breakfast and have
their eating window and like nine or 10 o'clock at night. So can we do we know from research where
this eating window should go? To maximize our metabolic health?
Dr. Panda: Yeah, so this is a question that's always
Dr. Mindy Pelz: you go, you've answered this 1000 times.
Dr. Panda: It's certainly personal. It all depends on your personal life. Because there are two
things, one big thing is in the pursuit of perfection, we should not give up what is good for you.
Right? We always think about okay, so that is, it has to be the super optimized, perfect plan, but
then it doesn't fit my schedule. So maybe I should give up at 18. No, that's not true. So let's
break it down to what time of the day, what happens in our body at different time of the day, so
that you can actually figure out when, when is the ideal time for you? So so let's start with waking
up. So when we wake up, that's the time when we have the maximum stress hormone, cortisol. So you
may be saying that, okay, in the daytime, you're too stressed in the evening, you're trying to
juggle many things, you're stressed, we're doing weightlifting, our strength training, whatever
you're doing and when the stress but actually the maximum cortisol happens within 45 minutes after
waking up, then the question is, well, we know that having food with cortisol is not a good idea,
because it doesn't,
Dr. Mindy Pelz: I was just gonna say that's not a great
Dr. Panda: answer. And then the other half of the story is melatonin, which is the night hormone
that rises throughout night reaches its peak, maybe two to three hours before we wake up. And then
it gradually goes down. And when we wake up, we still have nearly 30% of our peak melatonin level,
it has to go down completely for us to feel and that's why some people want the wake up little bit
earlier than when they're supposed to wake up. They feel lucky, groggy, sleepy, and if you take a
large dose of melatonin, try to fall asleep next morning, you're feeling still sleepy, because your
body still has, yes, yes. Melatonin. In addition to making your brain to sleep, it also makes your
pancreas to sleep. So that means when you eat your breakfast, most breakfast have some carbohydrate
that needs to be broken down to glucose and that needs to be absorbed by a body. So insulin plays a
big role in that but when melatonin is around, that insulin products and pantry has slowed down,
it's it's not completely starboard is a slow stuff. So in that when the boring, the stress on one is
high, and melatonin is high, for at least an hour or two, it's not that I time to, to eat. I think I
started saying that, once it wait for an hour or two, after waking up. And this has now amplified
and everybody's followed.
Dr. Mindy Pelz: Well, but it makes sense. It makes sense. Because what you're saying is that when
cortisol and melatonin are high, what you need to be metabolically healthy is not quite there. So it
would make sense to wait for these two hormones to go down and then eat so that you're putting
yourself in a little bit, a better metabolic advantage. But
Dr. Panda: here is another caveat. That is there is no human study yet sewing this effect. And the
reason is, it isn't is it's severely for that study, you have to actually bring people to the clinic
they should sleep there and then immediately after waking up you can start measuring melatonin and
cortisol and also keep them if bolus of food and measure their blood glucose for the next one and
half hour. It is a very difficult experiment got it. The converse has been done where people are
given food because melatonin also rises two to three hours before we go to bed. So then the question
is if you give a bolus of for very close to bedtime, measure melatonin and measure blood glucose
then that is a nice man between how high our melatonin is, and how bad our body is.
Dr. Mindy Pelz: Our sleep, I've seen it on my sleep on my my aura ring. I see it all the time if
Dr. Panda: that thing has been done, but the morning one, experimentally it has not been done. It's
just based on the idea that this is this might happen. But at least few in many of our studies, we
have seen people who just delay their breakfast. I'm not saying that, that delaying their breakfast.
No, not 10 o'clock, they're delaying a couple of hours in the morning, but they're not actually
advancing that dinner time that much because the delay itself is giving up 10 hours, they also
improve their blood glucose levels. So no, it's not too many people, we don't have enough power
there to say, conclusively, as I said, there is no very specific human study on this subject and
this topic that there should be a good morning fast of one to two hours, but the hormonal profiles
make sense. And then there are some studies, few individuals who delivered fast they benefit from
that Lucas profile. So those things are live. So So then
Dr. Mindy Pelz: eating in the light would make, like try to eat when it's like
Dr. Panda: bedtime. So unless somebody wakes up at two o'clock in the morning and habitually.
Dr. Mindy Pelz: Yeah, and but that's not there. That's that's shift working, which I want to get to
in a moment or, you know, even what happens when you change like you go into another time zone? One
question I have, and I've recently done a bunch of research on this is our microbes. How much are
microbes involved in this process of helping regulate blood sugar? And do the, the microbes have a
circadian rhythm that we need to be following? We're talking about hormone patterns, what about
those microbes do they have a circadian rhythm,
Dr. Panda: because the microbes actually change throughout the night so for example, I we go to bed
with has set up microbes in our garden, we wake up with a different set. The composition of our
microbiome actually changes throughout 24 hours. The reason is very simple. When we fast, as we fast
our InDesign has less food than the environment for this microbes changes. So they have so this
fasting environment, promote certain microbes and suppress other microbes. And then as we eat, and
we have food in our system that changes the environment. So again, they switch flips, and certain
type of microbes, florists, and other microbes will die down or will reduce in up. So there are
studies showing Yes, the microbial composition changes throughout 24 hours. And we are, at least
that is one thing that is universally now accepted from microbiome researchers is we should have as
many different types of microbes in our body as possible, particularly beneficial microbes in our in
our gut as possible because they do different things. They can break down food into different
bioactive molecules, Norris's so that the question is, right. Do you want all the actors on the
stage at the same time? Or do you want the actors to come do their part, a different chapter of the
play? By having a strong feeding passing cycle, you essentially have a nice orchestra of nice play
going on inside your guard so that at different times you'll have different microbes coming in doing
their part when the can florists and then they are disappearing, making room for the other set of
microbes to come in and do their part.
Dr. Mindy Pelz: So I'm wondering, then if we have different microbes at night compared to the day,
then what would signal that could be the change of light? Which then do those microbes? Maybe don't
you know, you've got the I love the way you phrase that when melatonin goes up to put us asleep, the
pancreas goes to sleep. But do we also have another effect of the microbes dramatically shifting and
those are not going to be as good at regulating blood sugar and or absorbing nutrients? Because
they're meant to be a different set of microbes for nighttime. Yeah, so
Dr. Panda: those things have not been investigated that well, at least in humans. And mice, we know
that there are different sets of microbes, they come up at different time. And again, there is not
much research on what happens to that microbial composition if we signed light on the mice at
different times of the night. But for The security and system. As far as we know, so far, the light
has to go through the eyes of the retina to reset the master clock in the brain, and then that brain
clock has to send signal to the rest of the body to implant CKD into them. So that is not direct
effect of light. On the micro, micro independent of the brain, it has to go through the brand. So,
there is not much research on that. And most of the microbiome microbiome changes largely connected
to the quality quantity and timing of food we eat. I said again, lastly connected, okay. And since
the quality quantity of food also changes at different time, because what we eat for breakfast is
very different from what we eat for dinner. They're also nourishing different types of microbes a
different type.
Dr. Mindy Pelz: So the microbes respond to the quality of food and when you eat, and now that you're
going to get the rhythm of these microbes, depending on your lifestyle behavior around those things.
Yeah. Now what happens if you change time zones? So this is something that I've been thinking about
with jetlag in general, can we use timing of food to either improve jetlag, you know, response to
jetlag. And what happens when I go to a completely different time zone, how long does it take my
microbes to really reboot themselves and get on to that new timezone?
Dr. Panda: Yeah, so the study is slowing. Initially, we thought that all the resetting of our
circadian rhythm to new time, John, occurs primarily through light, which is still true to large
extent, because light affects our sleep wake cycle. And a timing of four affects directly affects
our metabolic rhythm, which in turn influences sleep wake cycle. So then the question is, how can we
combine the effect of light and food? How do we optimize that when we travel to new time, John? Or,
for example, when you're doing shift work? How do you adjust to different sets. So this is, again,
an active area of research. And at the same time, it's a very difficult area of research because,
and all you have to properly change light and darkness, either in laboratory condition for mice, or
in humans in clinical studies, because you can, it'll be even more expensive to fly people from here
to Europe for yesterday. That would be tough. But still, the bottom line is yes, by adjusting the
food timing, at least in animal models in rats, they do reset to the new time, John much better, and
much faster. So the rule of thumb is okay, I need at least one day to adjust to a one hour change in
time, Joe. And some people may take even more than that. Just imagine when the daylight saving time
and standard time those things shed, some people can take up to a week to readjust to the new
timing, which is only an hour so but right, just imagine that your body can take one one week after
one week to adjust one. So in animal experiment, and at Arts people have shown that when you chance,
food timing, in sync with light dark cycle than this, that's the set the clock to the new time, John
are light dark cycle much faster than the dots that just changed the light dark cycle. And there is
no chance to put tiny data out there. So that brings up this important question like when you're,
particularly when we start travel, on the travel day, many of us we try to wake up very early in the
morning because, again, as estimize in the real life, yeah, if you're, if you're traveling with
somebody else, then you got to wake them up your take care few things in the morning. So you may be
waking up one or two hours and sometimes in three hours before your habitual wake of trying to get
to the airport or start driving. And so that's the circadian rhythm disruption to begin with,
because you have reduced your sleep time. And then when you release the new time, John, if you're
itching late at night, our reflexive behavior is well he should not go to bed, empty stomach so he
should eat something. And you're actually eating very late at night at the nucleus. And then in
between if you're flying across a continent or going from here to Europe or vice versa, sometimes we
entertain ourselves with lots of airline food. Liked It all right and watch movies and stay awake.
That, again is a lot of this stuff. So the bottom line is if we pay attention to what time you are
eating, what time is your flight or when you are teaching. And if you try adjusting your tire timing
of eating to the new time, John on the day of your travel. So for example, on the day of the day of
your travel, because you know, some people say that you should try adjusting two or three days
before it's very difficult because you're trying, you're preparing to do stuff. And then if you're
down only for two or three days and coming back, then it's time to add shift. If you cannot do two
or three tests before then, at least that day. So for example, if I, when I fly from, say West Coast
to East Coast, I also go through the same thing at work of an hour or two earlier to get to the
airport. And at 6am. In the morning, when I walk to the airport, it just cleans when I see people
lining up to get that morning breakfast morning bagel.
Dr. Mindy Pelz: me Tell me Chow and the line is long and the food is toxic.
I have the same problem. When I look at that
Dr. Panda: as like a commodity. I'm not going to work your card sit in the Aeroplan running, you're
not going for a 10k Your body doesn't need Yes, you can just go Yeah, pick out your neck pillow, an
eye mask and try to catch up on that slip that you lost. And yes, that's what somebody everybody
good travels to try to. And then in flight. And after you have rested minutes from West Coast to
East Coast is sometimes can be three to four or five hours flights that you can take out wherever
you have brought with you to eat or it will be done Clyde the man when you reach. Ideally, you're
reaching before nine or 10 in the night so you can reach and have some fun. So then the next
morning, and this is something that's very important that next morning, if you can go out for a
morning walk, slow jog, or be outdoors. After waking up. That actually helps tremendously to reset
to the new times. In fact, many successful people, I have met many successful businessman and other
professionals who travel a lot and have been healthy. I asked them so what's your secret? They'll
say? We'll tell you one thing. Never eat in flight.
Dr. Mindy Pelz: Yes, that's my secret. I don't eat on the flight.
Dr. Panda: Money. Get to the new place. If it is still there. Like, go for a run. Or next morning,
go for a run. Dexter morning, go for a walk if you cannot run because another thing about enjoying a
new place is to go early morning. Go for a walk. Typically eight, right? Within an hour after
sunrise because that's the time on the cities are completely empty. You feel like you're on this
Plex. You are the king or the queen. Yeah. You can take nice pictures without all the tourists.
Dr. Mindy Pelz: Yeah. So So then let me just recap what you just said. Because I think jetlag is
really an interesting conversation because more people are traveling and it's just becoming like, we
used to drive cars. Now we hop on planes. So are you saying if like couple of if I could a couple of
days before going to a big time zone shift. If I could start to eat in accordance to what that
timezone would be like, then that could help. It's one factor that could help with the transition
into that jetlag.
Dr. Panda: But it's not always ideal because for example, if you're flying from West Coast to
Europe, and that's a nine hour stripes, that means I have to wake up in the middle of the night.
Dr. Mindy Pelz: That's right, I'm about I'm doing that next. I'm doing that next week. This is why
this Friday, and I already Ah, so I've already downloaded the app that tells me like how I should be
going to bed a little different. And then I'm thinking okay, well now in light of this I'm like how
do I maybe put the timing of food and look at what my eating will look like when I'm there and start
eating in that pattern a couple of days before I go
Dr. Panda: I'm independent. If you're flying to Europe then I usually don't eat and fly because most
of the flights are less than 10 hours went from West because sometimes, but then you take out Yeah,
one hour after takeoff on one hour before takeoff when you cannot sleep so that leaves only 878 Max
Number seven to eight hours. And that's what you should be sleeping luckily is yet to catch up with
your sleep. And then to be fair, and then the breakfast in Europe is way much better than the for
this. Oh, yeah. So build up some appetite. Go have a good breakfast today.
Dr. Mindy Pelz: And the day, yes, yeah, don't deprive yourself just to set reset your circadian
rhythm is what I heard in that one. So, yeah, so that's good. Okay. So the next question I have to
ask you, and I'm sure people have been asking you this recently, is, you know, so much of the
research I've seen you talk about and you produce and bring out into the world has been about the
metabolic benefits of, of intermittent fasting, not just from a hemoglobin a one C, but when we're
looking at cholesterol and blood pressure, and several metabolic markers. And then we have this
headline is what I'm going to call it that came out like a month ago that said, if you intermittent
fast 91% increase in cardiovascular event. Can you talk a little bit about that? Because we are we
were flooded with questions on that. And I And when I looked at it, I thought this is an exact
opposition of the research I've seen you produce. So it didn't really make sense to me. Can you
address that? So people understand what that headline was? And was it accurate? And how does it tie
into the research you've done?
Dr. Panda: Yeah, so the let's try to explain what does that research. So what happens in the US
almost every couple of years, there is this survey that goes out to 1000s of people that are
normally paid to in a way that they present all atrocity or as land etc. And one of the questions
there is what did you eat yesterday, and how much you have not typically when you eat it, because
you know the questionnaire is not actually optimized to accurately say when this person but anyway,
so they collect this information. And then they also collect other information, whether the person
is smoker or nonsmoker, all the other information, which is called enhance less the salt form is
done in every two years. And that helps people to kind of look at the broad picture of what is going
on. With respect to health, what percentage of these people who are interviewed are obese, what
percentage are healthy, what problems they have, and all that stuff? That gives us a very good idea
of what is the state of the health and the country. But it doesn't give us a good picture of what
people ate. Because more than 60% of people in the service, they under report what they eat they
because it's very difficult. If you ask me what I ate yesterday, and all the person size becomes
very difficult to describe on top of that, when I will, yeah, breakfast at eight o'clock. Or maybe
they forgot and then people are not objectively asked When was your first calorie? What was your
Becca? So the survey is that a lot of studies saying that the survey is not the best way to collect
nutrition information. And in fact, there was a Mayo Clinic article saying how more than 50% of
people report metabolically implausible amount of food they eat for example 100 kilo person or
report that he or see at only 400 kilocalories. That's impossible. So, huh. So that is a lot of
problem with that data. So that's why that nutrition data has never been used to set policies about
what when and how much people so it to be very clear that nutrition data is rarely used to do set
any policy. Second, that near to sanitize also never used to say that whether you said it this way
to reduce the risk for other disease. So So essentially, this is a garbage in garbage out kind of
analysis because the nutrition data collect there is a report. So now in this study, what they
reported was they asked people who were eating less than eight hours, this is very important that
they asked, did they eat whatever they reported? Was it less than eight hours that didn't actually
say whether they were eating only one meal? Some people say that we had only one meal because maybe
that day they ate one meal or whether they are how much they had. There was no explicit in that
abstract there is nothing saying that how much they had. What they had is just one thing that they
ate within less than eight hours and then they try to match what kind of people are dying. Every
year than that try to match them to the subject, which is very indirect way of connecting, who is
who are the people who are dying and the next five or six years and then this called the National
death index and then connecting with, it's not that those specific people who are die because those
specific people are not longitudinally solid. So it was little bit right and difficult to make this
connection, you have to do some statistical with plus to make that connection. And another thing
was, this was not meant for public consumption this abstract. When we go to scientific meetings, we
usually put a small study and then see what people think it will give us feedback. And then we come
back to our lab and take our many, this is not a good idea, maybe I have to do more. So that's the
purpose of scientific conferences where we submit a very small article, less than 500 words, saying
this is what we do. And then sometimes we do put a poster so that means it's like two or three
fingers. Think of your high school science fair project, how people put a poster is a must like that
to get some feedback. And unfortunately, American Heart Association decided to put it for public
consumption in Slough scientific, this person in Addison, the scientific discussion. And then when
it came out, although it's not peer, reviewed, by other scientists, to the same rigor as any journal
article is peer review. There is no scientific discussion going on. What it went out, people got
really scared things out, we got calls from our face and saying that, hey, I want to withdraw from
this study, because I might die. And we go like, I know that our regulators, they would actually
say, well, now in light of this study this finding, do you think that you should continue this
study? And? And are we there are many scientists who got this kind of questions from the patients,
on medic physicians who got a lot of questions from the patient. So that's why we had to come
together and put a statement, and that statement is now circulating in social media. We put it back
to the American Heart Association, and then we decided that we'll put this statement out there.
Because they, right, because if you go back and ask the same thing, since a lot of people are under
reporting that calorie, including the obese people, they actually under report that calorie. So does
it mean if you take it along that line that would sound like if you eat less, you will likely become
obese? Which is also not true. It's not it's not caused? Yeah. So that's why Yeah, and then if you
look at what, how many people, the headline is 20,000 People study says this or something like that.
Unknown: Right? Yep, I looked like less than less than 500,
Dr. Panda: people actually reported that they were eating within eight hours or less than eight
hours. And if you look at them, that disproportionately more likely to be smokers. And we know that
smoking has a huge impact on heart disease and and many other compounds. And that they said they
never reported how many calories were they eating? And why were they eating for less than eight
hours? No, one minutes. This study actually collected data from many years ago, at that time,
intermittent fasting, fasting was not a thing. So the question is, why were they eating pointless?
So that also brings up another issue that we have seen with respect to sleep? People say that one
should sleep between six and half to seven and a half hours. The reason is, there are many studies
all over the world on millions of people. Now it will combine all the numbers saying that those
people who habitually eat between six and half to seven and a half hours significantly reduced risk
for many metabolic disease and morbidities. So then the question is, well, people who sleep less, of
course, we all know that, or advise them to sleep a little bit more. Those who sleep four hours or
five hours we tell them sleep more. But then the question is who are habitually sleeping for eight
hours, nine hours, because they feel like they have to rest that law. Professional athletes, for
example, they need more than eight hours of sleep. So are we going to tell them hey, your chance of
dying is much higher because you're sleeping more now because the lifestyle that the body demands
that long period of sleeping so they slip love, we should not ask them to decrease their sleep.
Dr. Mindy Pelz: Well say and well said, Yes, that's
a great analogy. What are your thoughts on the new weight loss drugs, because one of the things that
I keep hearing from a lot of people is that they they just not hungry. So in some sense, they're
fasting. And so but then the dark side of that is sometimes they're not hungry at all, and they're
bringing in very little calories, do you? Do you have any opinion on where we're gonna be heading
with these weight loss drugs, and the purpose of them is to improve metabolic health. But we also
know, intermittent fasting improves metabolic health. So where do you see it fit into this
conversation?
Dr. Panda: I think the drugs are extremely useful, because the reason why we need drug is what our
lifestyle is recommended. We, some of us fail to follow that lifestyle. So for example, for many of
us, as I said, to many, many years of eating habit, we are sensitive change our brain in a way that
our brain just wants those foods, it's very difficult for us to have control over our cravings. So
we cannot stop our events, if we know that this is not how they we just, we just go and have that
big portion size, because we don't our brand doesn't get the signal that you have stomach is full.
So it becomes very difficult to control the hours to hit. And in that way, in those cases, those who
are BMI, say 35 Plus, and they have tried everything and they're not losing weight, they're still
having comorbidities, then it's okay to have this worthless drug or type two diabetes drug because
these drugs were essentially initially designed for managing type two diabetes. And they have been
very effective, they can reduce hemoglobin a one C substantially, that is very difficult to achieve
with metformin are the first line of drugs. So then the question is, well, we know that there are
many side effects loss in appetite. So that also leads to loss and total energy intake, loss and
macronutrients and micronutrients. And that spawning another industry of supplements and a specific
macronutrient support. And I guess we'll see this going on for a while. And I think the long term
studies, or the long term effect when it becomes more and more apparent, and maybe people will think
twice. So for example, there are studies showing that chronic use of this worthless, I won't say
worthless drugs, because they may be taking for something else but type two diabetes, the GLP one
receptor agonist, it does reduce our peristalsis motion, and our guts, gut doesn't move for as much
as it used. Some people develop gastroparesis, where it can say your gut goes through paralysis or
something in extreme cases. So that is embedded some vomiting and all that stuff that can be
chronic, even after you stopped it. Although the SK is still pretty low, it's not negligible. So if
there is a risk of developing this gastroparesis, or this gastric fan, even what percent of people
who have taken the drug for one year, and if you compound it over 10 years, then maybe 10% or so,
then you have to think twice to see okay, so can you can you manage it slightly differently. So, for
example, when I talked to many physicians that say that they try to put somebody on the lowest
possible dose for a while to see how they're reacting, and then they continue, maybe escalate this,
depending on the target. So most of it is actually prescribed for type two diabetes. They say the
person is responding well, and it's stabilized. The appetite is coming back slowly, then they
continue. And now the second thought is, well, if they don't want to, if the person doesn't want to
stay on this drop, then can they begin with very below toes and intermittent fasting or thymus
ating? Will that help them sustain the benefit of the drug without too much of the adverse side
effect? I was said that this is just a third and justice is a hypothesis. I haven't seen any actual
human study that has begun, but I hope somebody will start those kinds of studies why are the lowest
possible doses along with some form of intermittent fasting, timeless eating, along with healthy
nutrition our eyes, because we have to think about the macro and micronutrient balance. And I guess
that will be that kind of study will give us some idea. Okay, so is it good to combine this? All
there is no benefit. You know what
Dr. Mindy Pelz: stack it with?
Yeah, yeah. Beautiful, beautiful. Well,
I guess, again, thank you for letting me pick your brain. I'm a big fan of the research that you've
been doing. And the message you bring me I mean, you You've changed a culture in not just time
restricted eating, but also in all things light. And I love this idea of movement like this timing
has been, I feel like a part of the health equation that has not been talked about enough. And
you've just been such a champion of it. So thank you for that. I have to, I have to finish up on my
favorite question to ask everybody. Which is, what is health for you? Like if you could define
health? How would you define it? Because we're all chasing health. But often we're chasing something
we don't know how to define. Yeah. So
Dr. Panda: I almost say that the best biomarker of good health is to have a good circadian rhythm.
So in this sense,
Dr. Mindy Pelz: right, there you go. And what
how do you what do you see
Dr. Panda: every day so for example, when you wake up within said a few hours of waking up, you
should have a good bowel movement. Because having a regular bowel movement is the best thing for
your gut health. And I'm surprised to hear that so many young adults, particularly young women
actually don't have regular bungoma. And then the same thing with many older adults too, so and then
the second day is a yes, after waking up. And going outdoor, you should feel fully energetic.
Because the first half of the day is when we are really a lot of brand is a lot we can do more
complex tasks, we can take NZP to position. So that's another feeling that it should have it I'm not
saying that you have to wake up at six o'clock or seven o'clock. Whatever your habitual wake up time
is from waste of time. Plus, six to eight hours is your most productive hours of the day. That in
the late afternoon is served not have too much muscle pen, joint pen, X and other stuff, because
those actually limit our movement or musculoskeletal health, which is very important. And in the
late afternoon, you should feel energetic to go out to have physical activity. And then you should
also have healthy hunger in the morning. In the evening, as you're winding down. You certainly
naturally feel sleepy to go to bed is to not be taking a sleep ad or sleeping pill to fall asleep.
And to have this body's ability to sleep without any sleeping, sleeping head and to be in bed to get
some restorative continuously for at least six hours. I says at least six hours because as you get
older, some of us have difficulty falling asleep staying asleep for Morton's continuously for six
hours, then this is my definition of help with goals once our circadian rhythms. I love that no
going then we know that everything else falls into inside this.
Dr. Mindy Pelz: Yeah, amazing. Amazing. Well, I love all your EQ your explanations and metaphors and
analogies and just just appreciate the work you're doing. So where did it where can people find your
book and and you have an app? Like how do people find some of the really cool stuff that is
available to them to interact with your work?
Dr. Panda: So I have two books now one of the circadian core that was published a few years ago, and
now it has been translated in 19 or 20 different languages. That's, that's quite nice. That's quite
satisfying, gratifying to see. And that the second book was mostly on diabetes, because I realized
that nearly half of the adults in the US are pre diabetic or diabetic and once you get type two
diabetes is a very nasty disease because once you get diabetes, then it affects almost the rest of
your body. And so how you can Mattis prevent man as diabetes, type two diabetes, particularly with
circadian optimization. That's the topic of the second book, this Akkadian diacritic score. And then
of course, we do a lot of research which can be very complicated for people to participate in. So
that's why we He synthesized all of that research around timing of food slave light exposure and
exercise into a simple app called on time health. And it doesn't sell it tells people to be on time
with their own circadian clock. And that way they can amazing, and they don't have to do too many
counting calories or counting person size, I guess what I say is, once we have a good control of our
time, whether it is in your personal schedule, or with your help, then you have a great sense of
urgency that you are in control. And once you control the timing for than what we see a lot of
people they feel that they are in control of the quality and quantity of their foot. Similarly,
amazing. Once you set a time to go to gym, you just had to go to gym, you don't have to think about
what you will do. You have to just go to the gym, and then you will find things to do. And that will
improve your cardiovascular health and Stripe clinics. Similarly, just keeping track of time,
Dr. Mindy Pelz: I feel like the general theme of this podcast could be like time the missing piece
to a healthy lifestyle. Like it's so interesting to me like how we talk about everything you're
supposed to do. And we have left out of the equation, the timing of all of that. So thank you for
highlighting that. I think it's I think everybody's gonna get a lot out of this. So appreciate you
and yeah, keep doing all the amazing work that you do so
Dr. Panda: much and have it perfectly circadian day
Dr. Mindy Pelz: I will I definitely will. Thank you. Thank you so much for joining me in today's
episode. I love bringing thoughtful discussions about all things health to you. If you enjoyed it,
we'd love to know about it. So please leave us a review, share it with your friends and let me know
what your biggest takeaway is.