Episode 121: The Relationship Between Food And Sleep With Dan Pardi

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Thanks for joining us for episode 121 of The Ancestral RDs podcast. If you want to keep up with our podcasts, subscribe in iTunes and never miss an episode! Remember, please send us your question if you’d like us to answer it on the show.

Today we are thrilled to be interviewing  Dan Pardi!  

Dan Pardi’s life’s work centers on how to help people live healthfully. He is the CEO of humanOS.me which leverages a novel behavior model to promote health fluency, skill development, and lifestyle insights to help people master their health practice.

He does research with Psychiatry and Behavioral Sciences Department at Stanford and the Departments of Neurology and Endocrinology at Leiden University in the Netherlands where he investigates how lifestyle factors, like sleep, influence decision making, cognitive performance, and metabolism. Dan also works with Naval Special Warfare to help the most elite fighters in the world maintain alertness and capable mental performance under challenging circumstances.

He currently serves as Board Member for StandUpKids.org, as a Council Director for the True Health Initiative, and Advisor to several health oriented companies, an editor for The Journal of Evolution and Health, and formerly as Board Chairman for the Investigator Initiated Sponsored Research Association.

We know that what we eat and how much sleep we get are major factors in health. But did you know that food and sleep are intricately connected so that the quality of one has a direct effect on the other?

Dan Pardi is here for a conversation packed with information about the emerging science of chrononutrition. Just some of what discuss is how what we eat is just as important as when we eat, food components that affect circadian rhythms, and guidelines for food timing. You’ll also come away with insight into how much sleep you should really be getting and how factors involved in sleep affect your daily performance.

You won’t want to miss this episode as Dan shares insight into the science and translates it into practical tips you can implement to optimize your health.

Here is some of what we discussed with Dan:

  • [00:04:56] The concept of chrononutrition and how this influences what and when we eat
  • [00:13:48] The value of animal and epidemiological research
  • [00:15:51] Guidelines for food timing
  • [00:25:16] The importance of understand your eating behavior when adjusting meal timing
  • [00:28:51] The effect of light exposure on the master clock, and the importance of finding consistency when experimenting with fasting cycles
  • [00:36:07] Food components that affect circadian rhythms
  • [00:44:27] Addressing the myth that you are more insulin sensitive later in the day
  • [00:49:15] Research that suggests eating protein and fat in the morning and carbs later in the day is a good meal timing strategy
  • [00:52:42] The recommended amount of sleep you should be getting and how factors involved in circadian rhythm and sleep processes affect your daily performance


Links Discussed:


Laura: Hi everyone! Welcome to Episode 121 of The Ancestral RDs podcast. I’m Laura Schoenfeld and with me as always is my co-host Kelsey Kinney.

Kelsey: Hey everyone!

Laura: We’re Registered Dietitians with a passion for ancestral health, real nutrition, and sharing evidence based guidance that combines science with common sense. You can find me at LauraSchoenfeldRD.com, and Kelsey over at KelseyKinney.com.

We have a great guest on our show today who’s going to chat with us about the influence of food on sleep quality, and sleep on food quality. It’s a great interview and we know you’ll enjoy listening to it as much as we enjoyed recording it.

Kelsey: If you’re enjoying the show, subscribe on iTunes so that you never miss an episode. And while you’re there, leave us a positive review so that others can discover the show as well!

And remember, we want to answer your question, so head over to TheAncestralRDs.com to submit a health related question that we can answer or suggest a guest you’d love for us to interview on an upcoming show.

Laura: Before we get into our interview though, here is a quick word from our sponsor.

“This episode is brought to you by Paleo Rehab, a five week online program designed to help you recover from HPA axis dysfunction, also known as adrenal fatigue. Is your perfect Paleo diet and lifestyle leaving you exhausted? Now is the time to start feeling the health and wellness you know you deserve. If you’re sick and tired of feeling sick and tired, and are ready to take back your health, then head over to MyPaleoRehab.com to get your free 28 page e-book on the 3 step plan for healing from adrenal fatigue. That’s www.MyPaleoRehab.com.”

Laura: Welcome back, everyone. I’m really excited to introduce our guest for today, Dan Pardi, whose life’s work centers on how to help people live healthfully. He is the CEO of humanOS.me which leverages a novel behavior model to promote health fluency, skill development, and lifestyle insights to help people master their health practice.

He does research with Psychiatry and Behavioral Sciences Department at Stanford and the Departments of Neurology and Endocrinology at Leiden University in the Netherlands where he investigates how lifestyle factors, like sleep, influence decision making, cognitive performance, and metabolism. Dan also works with Naval Special Warfare to help the most elite fighters in the world maintain alertness and capable mental performance under challenging circumstances.

He currently serves as Board Member for StandUpKids.org, as a Council Director for the True Health Initiative, and Advisor to several health oriented companies, an editor for The Journal of Evolution and Health, and formerly as Board Chairman for the Investigator Initiated Sponsored Research Association.

That was a mouthful! Dan, you’re busy!

Dan: I am. I do too much.

Laura: And you’re a dad, so you do it all!

Dan: Yeah, exactly. Those are my priorities: work and be a good dad.

Laura: Awesome! I was stumbling a little on some of that stuff, but hopefully I pronounced everything. Is it Leiden University in the Netherlands?

Dan: It’s pronounced Leiden.

Laura: Darn, I thought I got it. Oh well. Well anyway, you’re very busy. You have a lot of lot of different pots in the fire and a lot of different interests. I know for us, we were going to talk about sleep primarily today, but you have lots of great information on your website about not only sleep, but things like nutrition, just general tips for improving health, exercise, that kind of thing. We just love the work that you do, so that’s why we’re really happy to have you on the show!

Dan: Thank you.

Laura: Like I said, today we’re going to really focus on the nutrition and sleep connection. The connection is interesting because it definitely goes both ways and we’ll talk about kind of a bi-directional relationship there.

When we were looking over your blog before preparing for this interview, we saw you had this really interesting concept that you had talked about recently called chrononutrition. Can you explain to us this concept and how this influences what and when we eat?

Dan: Absolutely. This is one of those subjects in health, I almost think of it like the microbiota, so these are all the gut bugs that we have that we are now beginning to appreciate the importance of this relationship between the bugs in our gut and how our systems function in our body.

Similarly, circadian rhythms is now one of these bigger fields that we’re appreciating its value to our health. Ten to fifteen years ago neither of these two components that are getting so much attention in press were a part of any health model that was prescribed or just describing why health happens and when it doesn’t. It’s pretty cool to now see how our scientific advances are leading to new areas of opportunity and deeper understanding into how the body works.

So what is chrononutrition? Well, the bigger field is circadian rhythms. A circadian rhythm is a repeatable 24 hour process that is mostly orchestrated by light coming into the human eye. We have a master clock in our brain and that master clock is synchronizing with a light/dark cycle of the environment. When we don’t get adequate light, adequate being according to what our ancestors had perceived over the millennia…so light dark cycles depending on what season it is, bright sun during the day, dim in the evening, dark but with some moon light at night. Anyhow, that has a very powerful effect on the timing of our body rhythms.

We have this master clock in the brain and there are then clocks, they’re called clock cells that are in every tissue, every cell of our body, and that master clock will help to synchronize those peripheral clocks and that will let the body know what time to do what function. These are things like cell cycle repair and growth processes, when you feel like eating or going to the bathroom, sleep itself is actually a circadian rhythm. The reason why we tend to sleep more at night and be up during the day is because that pattern is trained by this master clock system that we have.

We’re now appreciating something called chrononutrition, which is the influence of food on these different peripheral clock tissue cells and how that will then determine or influence how well we process them and overall the state of health. It’s another important contributor to the state of health.

To give you a little more sort of specificity, the body tends to want to be able to not do competitive processes at the same time. There’s the terms anabolism and catabolism. Anabolism is the building up of tissue and catabolism is the breaking down of tissue. The body wants to separate those so it’s not doing both simultaneously, it’s doing one during one period, and then another during another process.

All of this is meant to sort of orchestrate energy production to meet energy needs. When we’re up and physically active, our body has a way of creating energy that is then helping us go about our daily activities. And at night, t’s sort of the opposite. There’s different energy that is being used and in different quantities, and it’s also expecting a long fast because we don’t eat while we’re sleeping.

That’s generally the concept. Why this has sort of become more interesting aside from just the scientifically understanding how the body works is because we also know there’s two very big topics right now that are also emerging into our understanding of health and how to promote it which is fasting and time restricted feeding.

Fasting can be a lot of different things, but it’s basically the period of time when you’re not taking in calories. Everybody endures an overnight fast. It’s the time between your last meal of last night and your first meal the next day.

There’s some evidence now that extending that window is good for things like cancer. Depending on the length of that fast, it might trigger a process called autophagy which is an intercellular process that will break down broken down proteins, and protein aggregates, and viruses, bacteria. It’s generally a housekeeping process. In fact, I believe the 2016 Nobel Prize went to a man whose life’s work was on understanding the subject better. Really, really important to human health. That’s a pretty hot topic right now.

But then there’s also the timing of your food. I’ll mention one other thing. So then there’s a shortened eating window or time restricted feeding, and that means that you eat all of your meals between a certain window every day. So just for simplicity sake, let’s say that window is between 9:00 a.m. and 7:00 a.m. There’s some thinking that well, what happens if you actually narrow that window and let’s say ate between only 11 and 6, or noon and 5? That’s one question is how narrow can that window be? Can you actually get some health benefits from that?

And then what is the timing of that window? So is it if you only ate between let’s say 1 and 7, would that be the same as even if the window was the same length, but it was shifted from between let’s say 8 and 1 in the afternoon and you didn’t eat otherwise until the next morning?

There’s a lot of research that’s going into that right now and we’ve been exploring that. Greg Potter, who is somebody who does some writing on my team, and he has a Master’s in Exercise Physiology, and he is doing a Ph.D. in chrononutrition which is the feature of this several part series. And we also have recently done a podcast together, which is not published, with Jeff Rothschild who is an RD. We talk about this, so fasting, and when should that period of time where we’re eating happen, and all that.

But it’s really, really interesting and it all kind of came back to some earlier research that noticed when mice eat at a time when they’re typically sleeping, even if they’re eating the same amount of calories over a 24 hour period, they’re expending the same amount of calories, or at least in terms of having the same amount of physical activity as a control group. That is essentially doing the exact same things, but eating at a time when they usually eat. Well that group that is eating when they usually sleep, they will become obese in the course of six weeks and have a significant weight change relative to the group that that was just eating during the regular time.

That had then been repeated and explored in a lot of different ways. Even just having bright light on or some light on at night was…this was some work by Laura Fonken…that caused the mice to become obese as well because it shifted the timing of their food intake to later in the day.

And so, yeah, this is a really promising area to both explore further in science and then to turn into health interventions that can help us better control over metabolism and weight.

Laura: I think that’s a great segue to the next question since like you said, this topic is really hot in the research field. Anytime there’s a topic that is getting a ton of research as a timely way, like the microbiome, chrononutrition, that kind of thing, there’s going to be a lot of data that comes that isn’t necessarily translatable into real life.

So we always like to take these kind of bigger research topics and say, okay, what can you actually learn from this that affects the behavior or the choices that you make during the day? Because at the end of the day, we don’t want to say this is the perfect thing to do and this is what the research says if it’s not a fully supported theory. But there are probably a lot of things that come from that research that are just generally good practices.

On that note, are there some general rules of thumb for food timing that you feel are pretty well supported by the research at this point? Or do you think that this question needs to be individualized to the person that is making this decision?

Dan: It’s a really good point about research. It sort of makes me frustrated sometimes when I hear on the interwebs people talking about this is terrible research if it’s epidemiological or animal. All research has its place and it enables us to answer or ask and address certain types of questions. When some people will sort of over impute value to just one animal study or the epidemiological work, that can be problems.

But the way that we do science is we ask these questions in different manners and then you look at the totality of the evidence to try to piece those tea leaves together to say, okay, what does this body of work tell us? And you usually have hopefully a clear, but imperfect direction about what you can do to intervene.

That’s pretty much how science typically works, but it’s cool because a lot of the animal work can unveil mechanisms that help us understand what’s sort of happening in the background and that might enable us to engineer lifestyle interventions and/or drugs that could sort of help people do better. That’s how I sort of see that. I just wanted to address that real quick.

But what was the question again? I forget. Sorry.

Laura: No, that’s alright, I get it. I think the science piece, like you said, it’s not the scientists that are doing bad studies or saying that this one mice study should then inform an entire population’s decision about food. I think that’s just the typical, almost like the pop culture end of the science where any time a study comes out, they want to kind of blow it up into this like, what should we do about it?

The way that science works is definitely a positive force for learning. It’s just I think in the age of Google, it just tends to be something that gets too quickly translated into prescriptions for people that might not be totally accurate or fully understood.

So for you, knowing what you know about the research, and knowing about like how much of this research has been replicated and applied to humans, that kind of thing, are there general rules of thumb for food timing that you think apply to just the general population? Maybe not everyone, but most people. Or do you think that this timing question is really dependent on the individual?

Dan: When talk about food timing, it has a lot to do with your biological time which it’s a difference between the actual time of the day.  Some people might just wake up later and go to bed later, so their biological timing is different than perhaps yours and mine.

There actually are some dependencies. So if for example, you go to bed really late and you eat really late, and obviously if that’s the pattern that you maintain, you’re getting artificial light. If you were sitting in darkness, well darkness will trigger a hormone called melatonin. Melatonin will suppress pancreatic beta cells from releasing insulin.

And what does that do? If you have any carbohydrates in your meal, it allows them to circulate for longer without being stored in various tissues throughout the body. That’s a great mechanism for the body to be able to keep blood glucose levels higher across the night when you’re fasting. It is all very much orchestrated, and so there is this important relationship between our natural environment and then the behaviors that we’re engaging in. I just wanted to mention that.

But what I would say are some signs that we have right now of ways to sort of intervene is it appears that eating your calories earlier in the day is favorable over eating them later in the day. That’s one indication. So whether it’s animal studies or moving into human work, then we see when this is sort of probed in various ways, that that seems to be pretty consistent when you have a shifting of the total amount of calories that you are eating to later in your day, that can be problematic.

There’s two questions there. Is it that you eat more calories later in the day because you’re sort of tired and you’re more likely to make poor food choices? Possibly. Are you also more likely to then disturb your sleep with a big meal late at night? Possibly. And then is your body just simply handling those calories less effectively? Are you inducing less metabolic thermogenesis or body heat in response to food and then therefore storing more? That’s also a possibility, too. You’ve got multiple different factors that are at play.

So if you eat the same amount of calories earlier in the morning, you tend to both have more physical activity throughout the day…and a lot of this stuff may or may not be perceptible to you. It might just be things like fidgeting or non-exercise thermogenesis, so you’re expending more calories in a subconscious manner. You also might recognize that you might be more physically active as well. You sort of get fewer calories from what you eat by eating them earlier in the day.

It also depends on like what you eat as well. The research indicates that high fiber, high protein has a satiating effect so that you take in less calories over the course of the day by not only eating earlier but having those having a higher protein, high fiber for breakfast.

So that’s one. That is your, I would say like the when do you want to eat. So that’s earlier. Now does that mean as soon as you wake up? I don’t think that it has to be like that. In fact, I usually wait several hours before I eat. I’m not really hungry right away. I did experience or explore just not eating. For a lot of people it’s natural to just not have breakfast because you’re not that hungry in the morning. So if you have a cup of coffee, you can get on with your day.

Unfortunately, because that is an easy way for people to do it, there are some signs that it’s not that healthy for you. It’s disappointing to see that. Again, because the way that the research looked at it, if you maintained that pattern all the time, so you just didn’t eat till noon and your body was used to that pattern, then some of those acute effects negative effects that you see from skipping breakfast might actually disappear at once your body acclimates to that regular eating behavior. That’s one possibility.

The other possibility is, or the other opportunity is to try to eat at the same time pretty much every day. So instead of having lunch some days at noon and some days at 3:00, that’s kind of a broad window there, but you actually are eating like pretty regularly.

In response to one of the articles that was published, a person who I know wrote in who was a track coach and she said that’s so interesting. She was a coach at Rutgers for over 30 years and she said one of the big coaches at the school who was pretty famous, he said just good athletes are like clocks; they eat the exact same time every day. She was sort of reflecting on her own experience coaching people with this new science. I thought that was pretty interesting.

So yeah, that’s one thing. Part of what the circadian rhythm is trying to do is prepare the body for activities, behaviors based off of previous experience. So if you’re eating lunch at noon every day, then your body is going to generate enzymes that prepare for food intake and nutrient breakdown. And when you eat out-of-phase, then the body doesn’t handle that as well. Very erratic eating behavior can then lead to probably less efficient metabolism. So that’s another idea.

We talked about eating calories earlier in the day versus eating calories later in the day. We talked about eating sort of at the same time, trying to eat around the same time that you did the day before, and the day before that, that you might handle calories better. And then the last is then what about that eating window? How long should you allow for that period, that off period if you will, of no calories at all?

This is an area where it’s still being explored. But some good work that took place out of Boston in breast cancer showed that women that had a 13 hour overnight fast had less cancer incidence, had better cancer outcomes if they were diagnosed with breast cancer, and less remission. That is pretty exciting because 13 hours is not hard.

Laura: Right.

Dan: I mean if you eat at 7, that means you’re not eating again until 8 the next morning. People can do that. I try to eat as early as I can every night. I tend to make, I have a very high fiber, big salad and then usually some fish and a little bit of starch, and then I try to eat early. And I drink a small glass, I would say two to three ounces of red wine every night. I like Dry Farm Wines. I just did a podcast with those guys. They’re doing pretty interesting stuff. I have no relationship with them, but I do like their product. I try to eat early and give my body some time to digest. Then I’ve been monitoring my sleep. And then what I also do is I’ll have some tart cherry juice sort of after my meals as dessert and then some chamomile tea maybe a little bit later.

That’s been my pattern for a while. I really do notice a difference between if I eat, for me I’m very sensitive to alcohol. If I drink too much or too close to bed, not good. And if I eat a big meal closer to bed, then the likelihood of having worse sleep is higher.

Laura: Cool. It sounds like the general consensus would be consistency is really important for people, which I would say depending on the person’s schedule, maybe it’s not so much about a certain perfect time of the day to start and stop eating, but get it consistent.

Dan: Yeah.

Laura: So don’t like eat breakfast half the week and then don’t eat breakfast the other half, or something like that. And then also just generally, now when you say calories at each meal, would you suggest having breakfasts that are larger than dinner? Or is it just more about not going the other direction?

I know for a lot of people they don’t have as much hunger in the morning so maybe they’re not going to eat of huge breakfast, but at least balancing their calorie intake across all three meals is better for them than hardly eating anything at breakfast and then eating a massive dinner.

Do you have any thoughts about is it that the breakfast actually has to be larger, or it’s just more balanced?

Dan: This is where human behavior comes into play. You’re right, it depends on people’s schedules. You can try to understand the physiology and you can adjust your behavior. If you tend to be somebody who just has one big late dinner and you’ve done “fine” with that, or let’s say that that’s how you typically eat but you’re actually looking for some opportunities too lose some weight or improve your health in various ways. Then yeah, you can adjust over time.

I also know that there are plate cleaners. If you skip breakfast, then that’s one opportunity to not take in more calories because you’re not that hungry, but then you eat lunch and you eat dinner. And if that person were to eat breakfast, maybe they’re not as hungry at dinner, but because the food was served to them they’re going to finish it because that’s their behavior around food.

Laura: Right.

Dan: That’s part of the problem with humans right that we could absolutely eat even in the absence of hunger, we can eat beyond fullness. Many of us do. I grew up in a generation where my parents were plate cleaners. There are starving kids around the world, finish this and my plate too. That really set a behavior for me. So I have to be mindful of that, but I also have to sort of work around my own tendencies.

So yes, I think it’s an important point where you can understand the science, but then you have to understand yourself, too, and then try to figure out what works. If you’ve always done something one way, it doesn’t mean you can’t do it another way. It might just mean you need a period of time to entrain to a new pattern. And once you’ve acclimated to that new pattern, it can be as natural as your former one. Having little patience with it too is good idea.

Laura: Right. It’s funny because I think with the concept of fasting as being good for circadian rhythms, a lot of times when people think about fasting, they’re imagining skipping breakfast and like you said having their first meal at noon. But from what you said, you might consider a fast just 13 hours and that really doesn’t make a huge impact on having breakfast or not. You can still have breakfast. Maybe it’s just a little later or maybe if you eat dinner a little bit earlier.

But I think there tends to be this belief in the Paleo community that to do fasting, that it has to be that like 16:8 style. Which for people that I work with, ones that are a lot of times struggling with eating enough or dealing with health conditions that can benefit from a higher calorie intake, a lot of times skipping breakfast actually impairs their ability to meet their goals.

There’s this belief that fasting is good for you, but then again it gets kind of narrowed down to this one particular style of fasting when the research doesn’t necessarily say that that’s the only way to do it. It’s cool to know that there are some different options for fasting that don’t require skipping breakfast or maybe just affect the way that you’re timing your meals.

We were mentioning that food can affect our circadian rhythms. It sounds like maybe both the central clock and the peripheral clock are impacted by food. Or is it just the peripheral clocks that get impacted?

Dan: It’s just the peripheral clock, yeah, the peripheral clocks.

Laura: So the central clock, is that 100 percent dictated by light exposure?

Dan: The numbers that I’ve heard is it’s above 98 percent entrained by light exposure coming into the eye.

Laura: Okay.

Dan: We have about one to two percent of the cells in the retina are non-visual photosensitive cells.  Visual photosensitive cells are like rods and cones that see light and transmit that information to the visual cortex.

They are cells that basically do the same sort of thing in terms of turning light into a nerve signal, but they go to the master clock instead. That’s their destination. And that will then affect the translation and transcription cycles of the genes that are located there, which then will have an effect on behavior, or hormones, or humoral factors, so things that are released into the blood, and also your autonomic nervous system. In those various ways, it can have an influence on the different clock proteins.

But one thing that happens sort of during these fasting and feeding cycles is we do have these fluctuations in humoral factors, or factors that are in our blood and like what sort of nutrients are circulating. These nutrients can be sensed by an enzyme called AMPK. This is an enzyme that’s actually, you want to induce it. A lot of the benefits of fasting come through the induction of AMPK. What this does is it will help to stimulate cellular energy production when energy availability is low. This is an energy sensor that is detecting when energy is low.

What AMPK does is it will tag these molecular clock proteins with phosphate groups. And when that happens, those phosphate, those now tagged substances are broken down more quickly. What that does is it sort of kind of enhances the oscillations of the circadian element of nutrient breakdown.

When your body is used to doing a behavior every single day, it does it better, it’s usually at the same time. A good example actually is alertness and awakeness. If you are if you are used to being up between let’s say 7 and 11, then you can do that well. When you then are trying to be up hours later than you used to, you can feel your body struggling to do it well. Similarly, then if you’re trying to eat nutrients at a time that your body is not used to it, then your body is not going to do that as well either. But that’s how this interaction takes place between the nutrients that are coming into the body and the clock proteins that are available.

Kind of going back to that main point, eating out of phase is tough. You could really see how people exploring with fasting could sort of mess themselves up if they’re having very erratic patterns. I think probably a better way to do it is to find a narrow eating window, a more narrow eating window. Perhaps instead of eating at 7:00 a.m., you wait until like 9 or 10 and then try to eat dinner early and just keep it there. You do not eat before 9 or 10 and you do not eat after 7 or 8, or whatever that might be. That is something that’s consistent.

Occasionally you might want to do longer fasts because other benefits can come from that. And again, the protocols for that are not perfectly detailed. But Jeff Rothschild, who I mentioned previously who was on the podcast that I did with Greg Potter, he is the lead developer of our fasting course, which humanOS is not launched yet, but we spent months working on that. We talk about what are the different benefits you get from different fasting cycles, the 5:2, every other day fasting, shortened eating windows, periodic longer fasts.

It’s a really exciting area. There’s more coming out on a daily. And yet like so many things, there’s more to learn. But I’ve come to think that fasting is a missing component to our health practice.

Laura: Interesting. I’ll have to check that out when it’s available. We have a podcast that we talked about the different types of fasting. I’m sure we don’t go into the detail that you guys are going to go into in that program, but it’s just really crazy when you actually start digging into the different perspectives on fasting, how many different ways of fasting that can be done.

It sounds like generally what you’re saying the research suggests is that just routine is ideal and that’s going to help our bodies function better if we’re doing something consistently than if we’re playing around with all these different one day doing a fast and the next day eating breakfast super early and kind of bouncing all over the place is not going to work as well for a lot of people.

And that actually may also describe or explain why a lot of times when you make a big shift in your diet, like if you suddenly change some significant factors like your macronutrient ratio, or your meal timing, anything like that you may not do as well in the beginning because of these circadian things that need to get kind of shifted to your new routine. But once you’re in a routine, it’ll start to work better.

Dan: Yeah.

Laura: It’s interesting what you said about the AMPK. Is it an enzyme? I’m trying remember exactly. AMP Kinase, so it’s an enzyme.

Dan: It is, yeah.

Laura: That that topic is something that I know Chris Masterjohn has been doing a lot of podcasts and little videos about energy status in the cell as being an indicator of whether or not we use insulin and glucose utilization, that kind of thing. Adding that extra complexity of the circadian rhythm on top of that, I know it makes it sound more complicated, but it kind of it’s cool to just hear how that can affect basically the cell’s utilization of energy. And maybe that translates to that obesity issue that happens when animals are eating outside of their normal day and night cycles.

Just kind of thinking about all the different ways these things can connect, but it’s just interesting because I feel like people tend to oversimplify the concept of calories in/calories out or insulin versus non-insulin promoting foods and how that affects obesity. It sounds like there’s so much complexity that also is driven by circadian rhythms that if you just ignore that, you’re not going to get the best results. It’s just cool to see how these different topics can all kind of interplay.

Now actually, I wanted to ask you if you know are there certain food components beyond just calorie intake that actually affect our circadian rhythms more than others, like certain macronutrients or micronutrients, anything like that that will impact our body’s clock system?

Dan: Yeah, there’s been some work that’s been done. It’s definitely basic science, so it’s early, but showing that saturated fat can actually have a deleterious effect on circadian functioning. Whether or not that actually has a real effect in the human body, is yet to be told.

But I found that pretty interesting in that work when they then applied a polyunsaturated fat in addition with the saturated fat, it actually had a mitigating effect so that the polyunsaturated fat actually prevented the negative impact of saturated fat on your circadian timing. That was one element, some research that is early, but interesting.

For example, so what do I do then for now, because sometimes the science….The way that I think about it is even if it’s just one animal study or basic science, I always try to translate it. Okay, if you were to actually make this actionable, what would that look like? Because that actually helps to stimulate hypotheses.

Laura: Right.

Dan:  If the risks are low to just trying it, if it’s not like hey, we’ll take this one animal study, they took this drug and then there was positive effects. Ehh, I’ll wait until the human trials.

But it’s a matter of having some DHEA and EPA with my burger at night if I have some meat and that might actually have a sort of positive impact on the negative effects the saturated fat could be having on my circadian timing, why not? Easy.

Laura: Right.

Dan: Unless it’s causing a problem, which it doesn’t, there’s no evidence that it would appear to, then it seems like the worst thing that can happen is I’m out a couple of bucks. So that’s one element.

There’s some other evidence that saturated fat however is not great for sleep. I know we’re talking more about the circadian rhythms, but there’s been a lot of research looking at how inadequate sleep, so whether that is truncated sleep time, or disturb sleep, so whether you’re having a lot of arousals or you’re not getting depth of certain stages, lots of ways that sleep can be disrupted. But anyway, inadequate sleep can have a negative impact on both metabolism and then eating behavior. My research looks specifically at that.

There’s less work looking at the impact of food on sleep. But some has been done. Marie-Pierre St-Onge is a researcher who’s done a lot of great work. She published in The Journal of Clinical Sleep Medicine a study where she had people in an inpatient unit and for four days…inpatient meaning they were able to monitor their sleep closely, monitor everything that they were eating…and they gave them a controlled diet for four days. On the fifth day the patients were able to choose their own food and eat whatever they wanted. Like most people, when you’re given access to cafeteria food, you might not make the best choices.

What they did is they looked at, they measured everything that they ate that day and then they looked at their sleep that night. They had that four day control period and then they said, okay, does sleep change the night where they were able to eat whatever they wanted? 1 -What did they eat and how did that differ from the control diet? And then 2 – How did sleep change?

What she found is sort of the three most notable factors were things that have an influence on sleep are dietary carbs, fiber, and saturated fat. The more fiber that you have, you had increased deep sleep and less shallow sleep. And we want that. I could go on for a long time about the importance of deep sleep, but this is essentially where the body is in a high state of repair, you are removing components that make you sleepy. When you don’t get a lot of deep sleep you might wake up the next morning with some of yesterday’s sleep burden, so you still feel sleepy. It also is really important for purging potentially neurotoxic substances out of the brain like protein aggregates like beta amyloid which accumulate with Alzheimer’s disease.

As we age there’s a natural declination of slow wave sleep the to the point where we’re getting maybe 15 percent of what the highest amount that we were getting earlier in our life when we’re around 60. And so there’s a lot of interesting science now that’s going into science and technology that’s looking at how can we amplify slow wave sleep because that actually might really resolve the burden that our society now faces with increased Alzheimer’s disease. Great podcast that I just did with Bryce Mander at UC Berkeley, in detail conversation about that.

But point being here is that more fiber across the day, didn’t have to be just your dinner meal…they looked at total amount of food that was eaten across the day. Higher fiber intake led to more slow wave sleep and less shallow sleep. That’s good.

More saturated fat was had the opposite effect. It decreased the amount of slow wave sleep, or I should say this, it associated with decreased slow wave sleep. None of this study was able to determine causation, but just looking at associations. If you ate more saturated fat, you saw that there was less slow sleep.

Laura: Quick question.

Dan: Go ahead.

Laura:  I was going to say what these changes, is this from baseline per subject, or is it just generally these people were getting less sleep? I guess my question is did they test them before the diet change to see what their baseline was, and then when they just ate whatever they wanted, then they saw a change for the negative there? Or was it comparing this subject to that subject?

Dan: It wasn’t with a subject design.  But other research has done just that where they did it with subject design. In this case they were looking at the group and they were looking at it to see, okay, this is what they ate and this is generally what the sleep was like. And then what happens to this group when they make these dietary changes? And yes, for those who ate more saturated fat, you did see these kind of changes in slow sleep and more fiber, etc.

One study, again, does not…this could be wrong. But it’s an indication that we have now. And we also saw that more sugar and non-fiber carbs across the day led to more arousals at night. Now these tend to be bad, so having less slow sleep or more arousals across the night, that is an indication of sleep fragmentation. Problematic? Hard to tell. I wish there was more research on this.

And then there’s always the longer term impact of good nutrition on the brain. While it’s very difficult to just look at how one day of food intake…it’s interesting to look at how one day of food intake will impact sleep tonight, but it’s very difficult to then look at four years of dietary, like sticking with a Mediterranean diet for example associating with let’s say better quality sleep. You could do that, but it’s harder to do it in a controlled fashion is my point.

Laura: Now I’m curious with these different macronutrient impacts on circadian rhythms and sleep quality, that kind of thing, there is the concept of carb backloading, which for those listening that are familiar with that, it’s the technique of eating very low carb throughout most of the day and then eating the bulk of carbs at night. There’s lots of people that believe that that’s a better way to take carbs in, and that you’re more insulin sensitive later in the day, and all these like circadian rhythm impacts.

What does the research say about timing of carbs? Do you find that later carbs do actually benefit the circadian rhythms? Or is there a negative impact? If there is any science on that, what do you see in the research?

Dan: Well you’re not more insulin sensitive across the day. One thing I would first say is that again remember that timing matters. But now let’s just say your last meal, you’re now observing consistent timing and it’s not too close to sleep, again, I try to eat dinner close to five as I can. It’s not always possible, but I try.

I’ll get back to this question, but my pattern my whole life is that I’m hungry at 5:00, and then I’ll snack, and then I’ll wait till dinner and then I’ll eat again.

Laura: Right, because you’re like I need to wait until dinner. I can’t wait until dinner, so instead of just eating dinner earlier, it’s like let me snack until dinner time.

Dan: Yes. I mean growing up I was basically stuffed by the time dinner happened and then I would eat two dinners. It’s definitely why I’m interested in the subject because I was overweight as a kid and so it simulated the desire for me to understand what was going on.

But yeah, so then to go back to the carbs. We also know that with dim light and melatonin production you’re going to have less insulin sensitivity, or you are going to be producing less insulin for clearing. The carbohydrates that are available in your circulatory system are going to stay a bit more available than they were if you were in bright light setting. So that’s one factor that matters.

Now if people are sort of having experience with it, a positive experience with it, I would want to look at it directly, but those are two things that I would say. So maintain watching timing. I wouldn’t have the idea of I’m going to have a huge bowl of carbohydrates right before bed because some people have felt like well that’s going to then cause me to get sleepy. I’d be a little cautious about that.

But the cool thing is that there’s a lot of cool technology that’s coming onboard where we are going to be able to look at our blood markers with much greater fidelity and frequency. We’re going to understand things like heart rate variability, and heart rate and readiness. There’s a lot of cool stuff that’s coming that’s going to help us be able to figure out what’s working for us well and what’s not.

Actually one friend of mine, Tim, wrote to me. Because after this series that we’re doing on fasting, he wrote back and he said this is so interesting because I’ve been experimenting with fasting so I don’t eat breakfast. He’s tracks like crazy. He’s like my blood markers have been really out of whack and I’ve been wondering what’s going on. He’s like so I’m going to make some changes and actually sort of try again. That I think is going to really enable us to sort of back up our theory about what is going to be good for us with some hard data that can help course correct.

Laura: Cool. There’s going to be more information that will help individuals make decisions that are best for them rather than just assuming it’s best because what tends to work on average.

Just to back up for a second with the carb backloading, are you saying that you don’t think that that’s accurate as far as the circadian rhythm perspective is concerned? Or you’re just not agreeing that you’d be more insulin sensitive?

I definitely understand with the circadian rhythm that the insulin sensitivity is the highest during midday I’m sure just kind of when we would naturally be eating during the day and not at night. I’m wondering if there is any sort of role of the cortisol awakening response that can affect insulin sensitivity at least early in the morning? Is there any thought there as to carb timing? Or maybe it’s just meal timing in general that’s affected and not necessarily worrying about carbs.

Dan: The dance of processes and hormones that takes place across the night in order to maintain blood glucose levels, which is a priority for the body because the brain wants steady supply of blood glucose and is very hungry, 25 percent of our calories that we take in go towards the brain. So it’s a very small part in terms of weight and it has a disproportionate share of energy usage mostly in the form of carbs to supply and support brain processing activities.

If you have disrupted blood glucose regulation, that can actually lead to problems of sleep because your body’s not getting the energy it needs over the course of the night in order to be able to maintain the active process which is sleep. The brain doesn’t just sort of go into this quiescent period where it’s not really doing much. It’s actually doing very active stuff. Part of that is it takes energy to rebuild, repair, to go through the different sleep cycle stages that we do.

And then there is some evidence that the timing of food or what sort of nutrient that you’re taking in actually does matter. I think that carbs at night totally make sense. There is some work that was done by Adi Neufeld-Cohen and what she looked at is the enzyme carnitine palmitoyltransferase. It’s an enzyme that shuttles fatty acids into the mitochondria. What she found is that this protein is produced at the highest rate when mice are awake and physically active. And again, this indicates that the mitochondria are best able to use sort of lipids during the wake period.

That is indicating that a high fat breakfast might actually be good for us because our mitochondria are then sort of getting the nutrient that they want at the time of day that they’re going to be using it. Now sort of conversely, so that’s carnitine palmitoyltransferase. But if you look at pyruvate dehydrogenase, which is an enzyme that turns the rate of glucose utilization, similarly mice produce the highest amount of this enzyme during sleep. That means that if you were to translate this to humans from mice, then you would say, yeah, a higher amount of carbs at night might actually make sense.

In fact, her team tested this hypothesis. By supplying the mitochondria with glucose, the metabolism of sugar was at its highest level as well. Eating fat and protein in the morning and in carbs later in the day might be a great strategy. Again, don’t eat too close to night, watch your timing. But that idea that you’re more insulin sensitive later at night is not true.

Laura: Yeah. Like I said this was things that the carb backloading community tends to say. Like you were saying, the insulin sensitivity piece, definitely not necessarily going to be more insulin sensitive at night. But there are maybe some benefits from eating carbs that have more to do with the brain’s utilization of glucose and what our body might prefer to run on either fat or carbs during the day versus at night.

I feel like that could be its own podcast probably. If you haven’t done one on that, you should because I know that our listeners would love to learn more about that.

I feel like I have like a million questions I could ask you. One thing I definitely wanted to find out because I know there is a lot of controversy about this question, and it might be a little bit too late in the podcast to get a ton of detail on, but how much sleep is actually really necessary for optimal health? Is there an amount of time that is agreed upon in the evidence?

Dan:  Yes. The National Sleep Foundation recommends getting a sleep period of seven to nine hours. Now sleep period and sleep time are different. If you were to report to me how most people would report sleep, I went to bed at midnight, I woke up at 8, therefore I slept eight hours. Nobody reports sleep as I went to bed at midnight, I woke up at 8. I had 85 percent sleep efficiency, therefore I slept six hours and forty two minutes and I had an hour and a half of wake time after sleep onset. That’s what a sleep study will tell you. But people don’t report sleep that way.

Some very interesting work was done by Jerry Siegel looking at hunter gatherer populations, the Hazda, the Tsimane, and the San, three different hunter gatherer populations that are remote from each other and they found that in studying them, the expectation was that they are going to sleep more than modern humans, and they didn’t find that. In fact they found they slept on the lower end, 5.7 to 6 1/2 hours of sleep time per night. That got a lot of press.

The problem is that’s actual sleep time, but their sleep period, so the time that they were in bed sleeping was about 7 to 8 1/2 hours, right in line with what The National Sleep Foundation finds. The idea is while sleep efficiency always sounds like a good thing, efficiency is something that like nothing’s being wasted, well it’s just natural for the body to have 15 20 arousals across the night. You turn over in your pillow in the morning, you don’t even remember them. Actually you remember them more as you age, so it sometimes feels like you’re waking up more even though you’re not. Sometimes you are. But anyway, that’s an important point to write down.

What I like to say is that you want to try to get complete sleep. So if you’re waking up by an alarm clock in the morning, then try to get to a situation where you’re going to bed early enough where your alarm clock is sort of like a stopgap. It would be rare that you would need it, but if you don’t wake up by this time then you’re going to be late. Give yourself enough time in bed to get that sleep that you need. You’re not going to sleep 8 hours if you’re in bed for 6. That’s a simple one, and then try to wake up naturally.

Under the condition of just sort of no external influences that’s promoting and the sort of insomnia or you’re not dealing with a particular issue, then just having really consistent timing of your sleep, just like with food, and then an adequate sleep period. There’s also individual variability. It’s not that you’re going to sleep the same amount every night. It’s going to change. Are you fighting an infection? Did you have a hard workout? Are you excited about something and your mind is ruminating?

All that stuff is natural, but what I would say that probably one of the most important things kind of like with food, just like with food, is that the timing of your sleep is going to have a surprisingly important impact on how well you feel the next day and how well you perform.

In fact, there are aspects of cognition that are dissociable from whether or not it is being influenced by your circadian or sleep timing and light timing processes, or actual sleep pressure which is how much sleep did you actually get. The point is if you usually go to bed at midnight and wake up at eight, and you have that rhythm every single day, but you go to bed at midnight and you wake up at like let’s say seven, so you missed an hour, you still might perform just fine because the timing of your alertness rhythm is really well entrained because you do the same thing every single day.

It’s complicated. It’s easier to explain this when you see something with some graphics because you can see the different components. But that’s an important point here is that your circadian rhythm and your sleep processes are sort of doing this dance. They’re actually working independently, and sometimes together. But overall your level of alertness or sleepiness at any point during a 24 hour period is primarily determined by this dance of circadian timing and then how much sleep pressure you’ve built up.

Once you understand sort of the more fundamental components of it, then the guidance is pretty simple. But it enables you to empower that guidance and to make sure that you’re getting not a lot of light before bed sleep, timing is consistent, you’re spending hopefully adequate amounts of time to get complete sleep so your body wakes up naturally versus by an alarm clock. I would say that’s pretty good general advice. There’s a lot to go into the subject though.

Laura: Well, like you said, it’s a lot of different interplaying things that can affect whether or not somebody is going to have the same outcome as another person. It’s weird, it gets super complicated, but I also think it gets really basic. It sounds like the most basic takeaway from this podcast is that consistency and routine is really optimal. So whatever you choose to do, if you can get that consistent it’s going to be much better than if you’re playing around with a bunch of different things or if like let’s say on the weekdays you’re sleeping 6 hours and then on the weekends you’re sleeping 10. Consistency seems to be the take home point today.

Dan: Yeah. That’s actually a different subject. If you’re getting six hours of sleep during the week, do you want to get recovery sleep? There’s different ideas around that. But I would say that if you’re getting 6 hours every night during the week and you can sleep 10 hours, that’s called your weekend differential and it’s an indication that you’re not getting enough sleep if you can sleep that much more during the weekend.

I would say in that scenario, you can mess up your circadian timing. But I would try to get that extra sleep because you’re going to perform better the following week.

Now how many times can you repeat that process? 6 hours then 10,  6 hours during the week, 10 hours the first night, and then 9 hours the second and then you feel groggy as heck Monday still. That is being investigated directly by saying, okay, it’s this process, can you continue to repeat this before you only recover 95 percent, then 90 percent. You’re not fully recovering. You’ve hampered your body’s ability to fully recover.

There is some evidence, there’s some research that shows that extended wakefulness, which is the same thing as sleep deprivation, actually has a neurotoxic effect on wake generating neurons within the central nervous system. So your ability particularly at the locus coeruleus, which is the primary center or loci of the neurotransmitter norepinephrine which is very important in orchestrating wakefulness, if you’re damaging those neurons, then that could influence how much alertness you can generate the following days.

It’s a great need we have because of how technology intervenes, and how we live, and how different that is from how we used to live for so long. And so knowledge is power. There’s a great tech coming, but the whole sort of point of what I do with humanOS is saying how do we harness the world’s best health information and then how do we actually empower people to then both use that and good technology that can help them?

For example, Fitbit, I’m a big fan. But so many people will buy it and then three weeks later it’s just collecting dust in their desk drawer. If you don’t really understand its value, then you’re not going to use anything even if it has no friction. You’re only going to use it if you’re like, oh I get it.

Laura: Really bought in.

Dan: Yeah, bought in, you’ve got to buy in. I mean I’m using mine five years later. I charge it. All that “friction” you could say of like having to charge a device every few days, it’s sort of de minimis if you think it’s very valuable.

Laura: Right. Yeah, you’re speaking to the girl who’s Fitbit is definitely done and dusted so would need an upgraded one if I was going to be using it.

Well Dan, I know you have a lot of really awesome information on your current website and it sounds like you have some really cool projects in the works. Where can our listeners find you?

Dan: Depending on when this comes out, currently publicly the website is DansPlan.com. I’ve not worked on that for about 18 months because all of my effort is going into humanOS unless. You could think of Dan’s Plan as almost like a beta tool in a way that is all based off of a behavior model that I developed in order to help people adopt and sustain different things that influence their health long term so it becomes a part of the process.

humanOS is going to launch very, very soon and we’re doing all sorts of course stuff, peer reviewed health courses. We’re launching a course on fasting, and the Mediterranean diet, and weight loss, and one called Road Of Health. Doing a bunch more, basically just scientific assessments, but done in a way where it’s more of like an executive summary that you can just get to the main point quickly and understand it for a lifetime.

Laura: Awesome.

Dan: That’s one thing we’re doing. A bunch of tracking tools and recipes. So it’s a really three dimensional approach to accompanying you on a day by day process to keep you healthy and help you upgrade your health smarts.

Laura: Very cool. If people go to DansPlan, is it DansPlan.com or DansPlan.org?

Dan: DansPlan.com. If we’ve made the switch, it’ll redirect to humanOS. If you go to humanOS.me now, it’ll just redirect to DansPlan.

Laura: Right. That’s what I was thinking because we had gone to the humanOS webite to look up what you were doing to prepare for the podcast and it redirected us to DansPlan. So it sounds like people will be able to find you, and we’ll make sure we have the updated link in the podcast notes for this episode. If people want to see Dan’s most updated work, we’ll have the link there. If we were just publishing today, what would be the best website for people to go to?

Dan: Just go to humanOS.me because it’ll either be humanOS.me or redirect and that’s the one you should remember to bookmark. So do it that way.

Laura: Awesome. That’s the new one. That’s where people are going to want to go if they’re listening to this in let’s say 2018.

Cool! Well thank you so much for joining us, Dan. Like I said, I feel like I could have asked you a thousand more questions. I had a few on my list that we didn’t get to, so maybe we’ll have to have you on in the future especially as these courses come out because they sound super interesting and I would love to check out some of them to not only learn for myself, but also to help my clients implement better lifestyle habits. Thanks again for your time. And we will look forward to having everyone here next week

Dan: It was a total pleasure. Thanks for having me on, Laura.

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I'm a women's health expert and a registered dietitian (RD) with a passion for helping goal-oriented people fuel their purpose.

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