The Circadian Code
Lose Weight, Supercharge Your Energy, and Transform Your Health from Morning to Midnight
Satchin Panda is one of the world’s leading researchers in the field of circadian biology. This book is a FANTASTIC distillation of what he and his colleagues have discovered and how we can apply those insights to our modern lives. I highly recommend it. Want to, as per the sub-title of the book, “lose weight, supercharge your energy, and transform your health?” Then pay attention to your body’s infinitely wise internal clock!! As Dr. Panda tells us: “The Circadian Code is a revolution in the way you think about diet, exercise, work, learning, and technology. Instead of counting calories or limiting food choices, you will learn that there is a right time to eat so that you can actually burn calories while you sleep. There is also a best time of day to exercise, to work, and to rest. Your body already knows this code: you just have to become aware of it and then follow its rhythm.” I’m excited to share some of my favorite Big Ideas so let’s jump straight in!
Big Ideas
- Circadian Rhythms“Around a day.”
- The Three Core RhythmsThree of them.
- Start with SleepYour day began last night.
- When to Eat: Time-Restricted Eating for the Win!Time-restricted eating for the win.
- Move Your Body!It does a Hero good.
“The observations I have made over the past twenty years, along with my colleagues and other researchers in the tiny field of circadian biology, are radically changing the way we understand how both the body and the mind optimally function. The science of circadian rhythms is actually a multidisciplinary field that includes biologists, exercise physiologists, mathematicians, psychologists, sleep researchers, nutritionists, endocrinologists, ophthalmologists, geneticists, oncologists, and more. Working together, we have found that simply adjusting the timing of how we live—and making easy lifestyle changes—is the secret to restoring our rhythm, and it will surely be the next revolution in health care. I invite you to learn what I have uncovered through my own research and through working with the best minds in each of these fields. I call this the circadian code, and by adopting these lessons you will make small changes to the way you sleep, eat, work, learn, exercise, and light up your home that will make a profound difference in every aspect of your health. In fact, the benefits you’ll reap can be far more effective and long-lasting than any medication or special diet.”
~ Satchin Panda, PhD from The Circadian Code
Satchin Panda is one of the world’s leading researchers in the field of circadian biology.
This book is a FANTASTIC distillation of what he and his colleagues have discovered and how we can apply those insights to our modern lives. I highly recommend it. (Get a copy here.)
Want to, as per the sub-title of the book, “lose weight, supercharge your energy, and transform your health?” Then pay attention to your body’s infinitely wise internal clock!!
As Dr. Panda tells us: “The Circadian Code is a revolution in the way you think about diet, exercise, work, learning, and technology. Instead of counting calories or limiting food choices, you will learn that there is a right time to eat so that you can actually burn calories while you sleep. There is also a best time of day to exercise, to work, and to rest. Your body already knows this code: you just have to become aware of it and then follow its rhythm.”
I’m excited to share some of my favorite Big Ideas so let’s jump straight in!
Download MP3
Download PDFAddressing the circadian clock is more than a diet. In fact, it’s not a diet at all. It’s a lifestyle. It begins with knowing when to eat and when to turn off the lights. Just paying attention to those small parts of your day will go a long way toward preventing and delaying disease.
Get the BookCircadian Rhythms
“You may have heard of circadian rhythms before; a 2017 Nobel Prize recognized this field of research for its impact on human health. But if you haven’t heard of circadian rhythms, don’t worry; the concept is very simple. The term circadian comes from the Latin circa, meaning ‘around’ (or ‘approximately’), and diem, meaning ‘day.’ Circadian rhythms are real biological processes that every plant, animal, and human exhibits over the course of a day. These rhythms are actually interconnected among species and are governed by internal circadian or biological clocks. ... almost each and every one of our cells contains one of these clocks, and each is programmed to turn on or off thousands of genes at different times of the day or night.
These genes influence every aspect of our health. For instance, when we are healthy, we can have a good night’s sleep. In the morning, we wake up feeling fresh and energetic and ready to get to work. Our gut function is perfectly normal. We have a healthy hunger and a clear mind. In the afternoon, we have the energy to exercise. At night, we are tired enough to go to sleep without much effort. Yet when these daily rhythms are disturbed for as little as a day or two, our clocks cannot send out the right messages to these genes and our body and mind will not function as well as we need. If this disruption continues for a few days, weeks, or months, we may succumb to all types of infections and diseases, ranging from insomnia to attention deficit hyperactivity disorder (ADHD), depression, anxiety, migraine, diabetes, obesity, cardiovascular disease, dementia, and even cancer.
Luckily, it’s easy to get back in sync. We can optimize our clocks in just a few weeks. By restoring our circadian rhythms, we can even reverse some of the diseases or accelerate cures, returning us to better health.”
Let’s start at the top.
The word circadian comes from two little Latin words: circa and diem.
It means “approximately a day.”
Know this...
EVERY SINGLE (!!!) plant, animal and human being (that would include YOU!), has a built-in natural rhythm that has been finely tuned over the last (tens and hundreds of!) million years.
Violating that natural rhythm is NOT a wise idea.
Good news...
It’s relatively easy to get back in sync. Let’s explore some Ideas on how to do exactly that.
We’ll start by looking at the THREE core rhythms of our lives.
The longer your circadian rhythm is out of sync, the greater the risk of developing a serious disease.
The Three Core Rhythms
“The clocks in different organs work like an orchestra to create three major rhythms that form the essential foundations of health—sleep, nutrition, and activity. What’s more, these rhythms are entirely interrelated and are also under our control. When they all work perfectly, we have ideal health. When one rhythm is thrown off, the others are ultimately upset, creating a downward spiral of poor health.
Your body’s rhythms work like a busy intersection that’s controlled by traffic lights. Any activity, from the way the brain functions to the way we digest food, works just like the flow of traffic: Each function is coming from one direction, but ultimately everything converges. If we don’t have the right traffic patterns, our rhythm is off. Because we can’t have all the body functions happening at the same time, we either get stuck in an interminable red light or, like cars colliding in a traffic accident, our rhythms will interfere with one another. And when we fail to pay attention to the traffic light, or when we work against the optimal rhythm, it confuses the signals and eventually compromises our health.”
Welcome to the chapter on “How Circadian Rhythms Work: Timing Is Everything.”
Dr. Panda tells us that our bodies can’t do EVERYTHING all at once. We have evolved to do certain things at certain times of the day (and night). There is a rhythm to these activities.
And, of course, that rhythm is circadian.
He tells us that we have THREE core rhythms.
These three core rhythms are tied to our THREE core fundamentals: Eating. Moving. Sleeping.
Let’s take a look at how to optimize each!
P.S. The three core rhythms are all tied to the “master clock” we’ve discussed before.
Dr. Panda tells us: “Scientists knew that cells communicated with each other, but we wondered if our internal clocks communicated from organ to organ. Scientists found a small cluster of cells that function as a master clock—just like atomic clocks are the master clocks for all other clocks in the world. These cells, collectively known as the suprachiasmatic nucleus, or SCN, are strategically located in the hypothalamus, the center of the base of the brain, which houses the command centers for hunger, satiety, sleep, fluid balance, the stress response, and more.”
If you are experiencing any physical discomfort, or changes to the way you think, don’t ignore them: They are early warning signs of chronic illness.
Start with Sleep
“Now that we know how our circadian code works, the next step is to hack it. We want to get the most out of our daytime activities and nighttime rest. The goal is twofold: First, we want to adjust our activities to the optimal times of the day that are most in sync with our clocks. We want to eat when we metabolize foods the most efficiently, we want to be active when our brain and body are functioning at their peak levels, and we want to get the right amount of sleep so that we can do it all again tomorrow. Second, we can fix disruptions and retrain our clocks to improve our health.
It would be a totally rational guess to assume that the first thing we need to fix is our eating pattern. But in reality, circadian clocks readjust best when addressing our evening activities, namely limiting our access to light and enhancing sleep. The reason is because sleep is not a passive experience. The human body begins to get ready the night before. Just like we start off the New Year with a celebration on December 31, sleep is the beginning of our biological day, not the end.”
Welcome to the first chapter in Part II: The Circadian Lifestyle.
Now that we know the three core rhythms (Eating! Moving! Sleeping!) it’s time to optimize each of them. And... We’d be wise to START with our Sleep.
For years (!), I’ve been talking about the fact that our day BEGINS the *night* before. This is the first time I can recall any author stating it so clearly.
As he says: “The changes you’ll make from reading this book that will be most profound will be created by monitoring your life from 6:00 p.m. to midnight.”
We may think that our sleep is the *end* of our day. But it’s not. It’s the BEGINNING of our day.
So... How do we optimize our sleep?
First, as we discuss in Sleep 101 and in the Modules on Sleep in the Mastery Series of Heroic Coach, we need to PRIORITIZE it. If we’re not getting the recommended 7-9 hours of sleep, we need to restructure our days to give ourselves the best shot at getting it.
As you’d imagine, Dr. Panda offers a ton of practical tips on how to optimize our sleep—nearly all of which are discussed in Sleep 101 and our Mastery Series.
For now, let’s focus on his discussion of how LIGHT impacts our sleep.
Dr. Panda tells us: “Visible light includes all the colors of the rainbow. Each color has a different wavelength. Red has the longest wavelength, and violet has the shortest. When all the waves are seen together, they make white light, or sunlight. Different colors within that white light activate three types of opsin proteins (red, green, and blue), which in turn identify these colors individually and collectively (as white light); The melanopsin protein is most sensitive to blue light wave and is less sensitive to red light. When melanopsin is activated by registering blue light, it sends a signal to the brain that any light is present, and the brain responds by thinking it is daytime, regardless of what time it really is. If you’re walking in the grocery store at night, your melanopsin is registering the overhead light and your brain thinks that it’s daytime and you should be awake.
Imagine that you have two light bulbs with identical brightness—one is a blue light and the other one is an orange light. In the middle of the night as you turn on the orange light, the light fires up opsin in the green cones (green cone opsin can sense orange light as orange is close to green in the rainbow) and your brain recognizes what is in the room. If you turn on the blue light, your blue cones fire up and you can see the same objects in the room. However, melanopsin cells barely fire up under orange light and will tell the brain it is night, while the blue light will register as daylight. So, if you spend an hour under orange light, your circadian clock may not be disturbed as much, but spending an hour under blue light will make your clock reset as if it is morning.”
Orange light vs. blue light.
Dr. Panda walks us through the precise science behind how our brains interpret each of those colors and why it’s a REALLY (!) good idea to reduce/eliminate the blue light when the sun’s down and, instead, have some orange-red lights on in your house—or, at the VERY least, DIM your bright blue lights!
Which is why, if you ever looked at our house from the outside after the sun goes down, you’d see an orange-ish red glow. If you don’t want to be quite *that* weird, wear some blue-light filtering glasses at night. Dr. Panda tells us about how manufacturers of those glasses were inspired by HIS and his team’s work!
Pro tips: If you have kids, swap out their blue-light night lights for ORANGE night lights. Dr. Panda talks about how this can lead to an extra HOUR of sleep. And, if you travel, consider bringing some orange night lights with you to navigate your way around the room at night! :)
P.S. If you haven’t checked out our Notes on Why We Sleep by Matthew Walker yet, PLEASE DO. It’s powerful. Also, check out Arianna Huffington’s The Sleep Revolution and Sleep Smarter by Shawn Stevenson.
Your performance at any moment during the day is primarily determined by what you did the night before—when you ate and how much you slept—because that is what sets your clock, which then primes your body and brain.
The body remains in fat-making mode for a longer time after a late-night meal. Only after 6 to 7 hours of not eating does our body begin to start burning some fat. This is the critically important aspect of TRE: to stop feeding the engine that is your body and let it run on the fuel it already has. This is the only way to prevent or reverse weight gain and, ultimately, obesity.
When to Eat: Time-Restricted Eating for the Win!
“Our findings underscore the importance of one of the primary goals of this program: to align your eating schedule with your circadian code. Start by establishing a 12-hour window for a week or two, and then try to decrease the time you eat by an hour a week. The reason to do this is that the optimum eating window is between 8 and 11 hours. This is because the health benefits that you get from eating within a 12-hour window double at 11 hours, and double again at 10, and so on, until you reach an 8-hour window. Eating for 8 hours or less may be feasible for some, or for many of us over a few days, but it becomes difficult for many people to sustain this over months or years. While the science at 12 hours is impressive, lowering your window (to as few as 8 hours) is significantly advantageous.
Time-restricted eating is never about counting calories; it is just about making you more disciplined about timing. We’ve found the best results for weight loss come with eating within an 8- or 9-hour window, and you can maintain this pattern until you get the desired results. Most of your body’s fat burning happens 6 to 8 hours after finishing your last meal and increases almost exponentially after a full 12 hours of fasting, making any amount of time fasting past 12 hours highly beneficial for weight loss. Once you’ve achieved your desired weight loss, you can go back to an 11- or 12-hour window and maintain that body weight. Of course, discuss your plans with your doctor before beginning any new eating program.”
THIS is perhaps THE biggest Idea in the book.
We’ve talked about intermittent fasting and time-restricted eating in the past.
Know this: Dr. Panda and his team DID THE RESEARCH that everyone is leaning on when they make their recommendations to eat in a constrained window!
He walks us through the FASCINATING research he did with mice.
Here’s one passage: “We compared one set of mice having free access to the fatty diet to a second group that had to eat all their food within an 8- to 12-hour period. What we found was startling: Mice that eat the same number of calories from the same foods within 12 hours or less every day are completely protected from obesity, diabetes, liver, and heart disease. More surprisingly, when we put sick mice on this scheduled feeding, we could reverse their disease without medication or change in diet.”
Note: THAT. IS. CRAZY.
Here’s a bit more context to make sure the power of that sinks in...
Feed mice poor quality food. Let one group eat all day, every day. They get very sick. Force the other group to eat that SAME FOOD within an 8-12 hour window of time. They do NOT get sick.
I repeat: SAME FOOD. Different eating windows. And... BOOM!
The mice who ate within 12 hours or less every day were, and I quote: “Completely protected from obesity, diabetes, liver, and heart disease. More surprisingly, when we put sick mice on this scheduled feeding, we could reverse their disease without medication or change in diet.”
Which brings us back to YOU!
When did you have your LAST bite yesterday? And, when did you have your FIRST bite today?
Seriously. Make a note. And, do the math.
If you had your last little snack at 9:00 p.m. and your first sip of coffee or tea (yes, THOSE count—ANYTHING but water counts against your fasting window!) at, say, 7:00 a.m., your fasting window was 10 hours and your EATING window was 14 hours.
THAT, the good PhD-doctor tells us, is sub-optimal.
Here’s how he tells us to consider approaching it: “Let’s start by setting an ideal time for breakfast. The moment you eat breakfast or have your first cup of coffee or tea is the beginning of your eating window. Once you set your breakfast time, stick with it. If breakfast begins at 8:00 a.m., dinner must end by 8:00 p.m. We’ve found that it’s healthiest to eat breakfast as early as possible. The reason is that the insulin response is better in the first half of the day and worse in late night. Besides, if you start early, you are also likely to end early, or at least 2 to 3 hours before going to bed. This is important, as melatonin levels begin to rise 2 to 4 hours before your typical sleep time. Finishing your meals before melatonin begins to rise is necessary to escape the interfering effect of melatonin on blood sugar.”
Note: There’s a LOT of goodness in there—including the fact that eating earlier is better than later because our body is built to eat earlier in the day not later.
And... Before we move on, I want to repeat this REALLY powerful line: “The optimum eating window is between 8 and 11 hours. This is because the health benefits that you get from eating within a 12-hour window double at 11 hours, and double again at 10, and so on, until you reach an 8-hour window.”
I repeat, this time in bold to make sure you get it: “The health benefits that you get from eating within a 12-hour window double at 11 hours.” And...“They double AGAIN at 10 hours. And so on, until you reach an 8-hour window.”
← That’s EXTRAORDINARY.
All of which begs the question: What’s YOUR new target, Hero?
P.S. This is personally life-changing for me because I thought I had a MUCH longer fasting window than I actually did when I factored in starting my day with a little concoction I have in the morning and some little snacks at night. FIRED UP to dial it in and go next level. YOU??!
Everyone should focus more on when they eat, instead of what they eat.
So, if you’ve wondered why diets haven’t worked for you before—it’s quite likely that you weren’t respecting your circadian clocks. If you eat late at night or start breakfast at a wildly different time each morning, you are constantly throwing your body out of sync. Don’t worry, the fix is equally simple: just set an eating routine and stick to it. Timing is everything.
Eating at the same time every day is one of the most powerful ways to maintain a strong circadian rhythm.
Move Your Body!
“Physical activity is just as important as sleep and good nutrition when it comes to good health. Daily movement improves muscle mass, muscle strength, bone health, motor coordination, metabolism, gut function, heart health, lung capacity, and even enhances how your brain functions. What’s more, exercise has a circadian effect, improving sleep and mood. Exercise literally relaxes the brain, reducing depression and anxiety and increasing our ability to experience happiness. Exercise is one of the best medicines. ... Whatever you choose, stick with it: Make physical activity part of your routine so it becomes a habit.
Exercise’s mood-boosting effect is critical to keeping you calm and integral to productivity.”
Exercise.
We know it does a Hero’s mind, body and soul good.
So... How’s yours?
Check out Movement 101 and our Notes on Spark by John Ratey, The Joy of Movement by Kelly McGonigal, and Movement Matters by Katy Bowman for tons of wisdom that Dr. Panda confirms and his research supports.
For now, know this... Exercising earlier in the day gives you a mood boost. 10,000 steps a day is a great target. Strength training in the afternoons is great but make sure you give yourself enough time to get your core body temperature back down so you’re not disrupting your sleep. And, as Tal Ben-Shahar puts it in Happier (and echoed in our Heroic Chats with Masters), NOT exercising is like taking a depressant!
Eating. Moving. Sleeping. ← What’s one little/big thing you KNOW you could do to Optimize?
Here’s to optimizing our fundamentals as we get in alignment with our natural circadian rhythms so we can get Heroically Energized, Heroically Productive, and Heroically Connected TODAY!
Day 1. All in. Let’s go!
We assumed that fasting for 14 to 16 hours would break down muscles and we would see a reduction in muscle mass. Actually, we found the exact opposite.
About the author
