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The Circadian Code: Lose Weight, Supercharge Your Energy, and Transform Your Health from Morning to Midnight

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When we eat may be as important as what we eat.

Like most people, you probably wake up, get hungry for meals and doze off in bed around the same time every day. If you’ve ever experienced jet lag or pulled an all-nighter, you know that this schedule can easily be thrown off kilter. But for some people, that imbalance—difficulty sleeping at night, hunger at odd times, or sudden fatigue at noon—is a constant. If you're one of those people, Dr. Satchin Panda, one of the leading researchers on circadian rhythms, has a plan to reset your body clock.

Beginning with an in-depth explanation of the circadian clock—why it’s important, how it works, and how to know it isn’t working— The Circadian Code outlines lifestyle changes to make to get back on track. It's a concrete plan to enhance weight loss, improve sleep, optimize exercise, and manage technology so that it doesn’t interfere with your body’s natural rhythm. Dr. Panda’s life changing methods show you how to prevent and reverse ailments like diabetes, cancer, and dementia, as well as microbiome conditions like acid reflux, heartburn, and irritable bowel disease.

288 pages, Hardcover

First published June 12, 2018

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Satchin Panda

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Displaying 1 - 30 of 406 reviews
Profile Image for Tiago Faleiro.
358 reviews118 followers
March 2, 2021
I've had sleep problems for as long as I can remember. I always went to bed late and did not get sleepy until way past midnight. At some point, I often took more than one hour to fall asleep. When I finally got into fitness in my late teens, I started to try to fix my sleep schedule. A little by little I managed to do so, but with great effort and it took many years. I've read a lot on sleep so I could better fix my schedule, and by extension, on the circadian rhythm which heavily influences it.

Someone recommended this book to me since Dr. Panda is supposedly an expert on the circadian rhythm. I already knew a ton about the topic and my sleep was decently normal, but I figured that I might find some extra information that I wasn't aware of and improve my sleep and quality of life even further.

That was a mistake. The book is bad, and I regret picking it up. I noticed it immediately and wanted to stop reading, but I figured I would finish it just for the sake of the review, so I can hopefully inform people better.

Everything that relates to the circadian rhythm is not too bad, especially in its most basic form. However, the author really makes some wild extrapolations, and his claims are way stronger than the evidence presented. Most studies are on rats, and the few human studies presented are often weak and preliminary. He also includes countless anecdotes, but I find it hard to believe that he doesn't recognize the heavy selection bias that entails.

The worst comes from the fact that this book goes well beyond presenting how the circadian rhythm works and tries to make a typical diet/self-help book. And because of it, the author goes well beyond his scope and makes a lot of errors. Here are a few:

- Fasting enhances fat-burning.
This claim is repeated throughout the book in several forms, but they are all wrong. They are based on an oversimplified model of how insulin works. Insulin response isn’t only dependent on the frequency of feeding. Yes, you will burn fat from reduced insulin while fasting, but if your eating frequency/window is smaller, you will just have a much bigger fat formation when you do eat, and in a 24h period, the effect is the same (Krieger, 2010). In a separate but similar claim, he also states that fasted cardio burns more fat. This is also wrong (Schoenfeld, 2014).

- Danger of high-protein intake
Supposedly a high-protein intake is not good for your health, and more specifically harmful for your kidneys. Surprise surprise, it has been researched, this is bonkers. (Phillips, 2016; Juraschek, 2013; Antonio, 2018). If you have healthy kidneys to begin with, high-protein diets are safe and healthy.

- Diet soda is bad for the gut microbiome.
This isn't false per se, but it needs to be taken into context. There are many kinds of artificial sweeteners and they shouldn't be lumped together. Only some have found to have an effect on the microbiome (Ruiz-Ojeda, 2019). In addition, many use incredibly unrealistic dosages, for example, the equivalent of 8L of diet coke per day (Harpaz, 2018). We can't assume a similar effect with moderate consumption.

- Coffee dehydrates you.
It does not. While caffeine is a diuretic, the water in the coffee compensates for this effect, and also the diuretic effect seems to fade for habitual drinkers (Killer, 2014).

There was also other small stuff that I can’t be bothered with, for example, he mentions leaky gut often and not once does he even mention that this isn’t a recognized medical term at all.

Like I said, most of what the author gets wrong is beyond the topic of circadian rhythm because he tried to make this an all-encompassing diet and lifestyle advice. However, there were a couple of things that I found quite concerning because they are related to the circadian rhythm.

One was about melatonin supplementation. While supplementation is not required, it can be incredibly useful for people struggling with sleep. The author covers this but then mentions a dose between 1mg and 5mg. This is way too high. For most people, this will have unwanted side-effects, such as waking up in the middle of the night or still feeling groggy the next morning. The correct dose for most people is 0.3mg (Alexander, 2018). If we average out the dose the author mentioned, he was off by a factor of 8. In his defense, such a dose is widespread, and most supplements have that dose, but it is incorrect nevertheless, and he should have known better.

The second problem directly related to circadian rhythm was that in the entire book, I don't think light therapy was mentioned a single time. This is unacceptable. It is one of the best forms of aligning the circadian rhythm when you don't get enough sun exposure, and one of the best treatments for sleep and circadian rhythm disorders. This is especially important for regions where it is difficult to get enough sunlight in the winter due to higher latitude. The author mentions this problem, yet mentions no solution as if light therapy didn't exist.

The book is a mess. There is definitely good information about how the circadian rhythm works, but nothing ground-breaking, and nothing that you can't get elsewhere without all the other misinformation. The last part of the book was the best, which goes over some promising research about how the circadian rhythm can influence cancer prevention and treatment, metabolic syndromes, immune system disorders, and brain health. I think it’s super interesting, but the evidence is constantly exaggerated, and it most definitely does not compensate for the rest of the book.

Sometimes he even contradicts himself. At one point he mentions that you may not experience any weight loss after a time-restricted feeding protocol, when previously in the book he talks about TRF as a close to guaranteed weight loss protocol. Sometimes his claims are so strong that I find it hard to believe this was actually written by an expert. "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." Notice the language: "only way". How can he possibly write this? Is he that out of touch that he is completely unaware of thousands of people that achieve and sustain weight loss with literally the opposite protocol of what he recommends, every single day?

Part of me hates this book because it is intellectually and scientifically dishonest. But another part of me hates it on a personal level because while I think that many of the claims are exaggerated or completely false, I nevertheless follow a TRF protocol. And I wish I had all the amazing benefits that the author claims! But I don't. I think it has some minor but worthwhile benefits (for energy, mood, and sleep), but nothing even close to how he puts it in this book.

In fact, I found it quite funny that he mentioned his exact schedule, including wake time, meal times, and bedtimes, and they're almost exactly the same as mine. I wish there was a magic bullet to health, but there isn’t.

Nevertheless, if your circadian rhythm is out of whack (and that’s very likely due to our modern lifestyles), I think it’s worth trying to improve it. You will likely experience better sleep, energy, and mood. However, this book is not a good resource for that. I will give you some helpful pointers here instead:

- Wake up and go to bed at the same time every day, including weekends
- Maximize blue-light in the morning through sun-exposure. If you can't, try light therapy
- Minimize blue-light around 2h before bed-time. Avoid screens and/or use blue-light blocking filters or blue-light blocking glasses
- Have a relaxing and consistent bedtime ritual before you go to bed (this was completely missed in the book and it is sleep hygiene 101).

This is 90%+ of the benefit you will ever get from learning about the circadian rhythm. If you further optimize it, you might also consider the following:

- Have your room as dark as possible. Ideally pitch-dark. Use an eye-mask if you can't
- Use earplugs and/or white noise if you wake up from outside noise
- Have your room slightly cool
- Have a meal close to your wake-up time
- Avoid having a meal close to bedtime (especially a large one)
- Exercise daily, but likely best if it's not close to bed-time
- Avoid caffeine later in the day (6-12h before bedtime, depending on the dose and your genetic caffeine metabolism)
- Avoid alcohol before bed
- Don't take long naps (keep them around 20mins), and avoid them completely after 2-3 PM.


Krieger, J. (2010). Insulin: An undeserved bad reputation, Weightology.

Schoenfeld, B. J., Aragon, A. A., Wilborn, C. D., Krieger, J. W., & Sonmez, G. T. (2014). Body composition changes associated with fasted versus non-fasted aerobic exercise. Journal of the International Society of Sports Nutrition, 11(1).

Juraschek, S.P., L.J. Appel, C.A.M Anderson, and E.R. Miller III (2013). Effect of a high-protein diet on kidney function in healthy adults: results from the OmniHeart trial. Am. J. Kidney Dis. 61(4): 547-54.

Antonio, Jose & Ellerbroek, Anya. (2018). Case reports on well-trained bodybuilders: Two years on a high protein diet. Journal of Exercise Physiology Online. 21. 14-24.

Ruiz-Ojeda, F. J., Plaza-Díaz, J., Sáez-Lara, M. J., & Gil, A. (2019). Effects of Sweeteners on the Gut Microbiota: A Review of Experimental Studies and Clinical Trials. Advances in nutrition (Bethesda, Md.), 10(suppl_1), S31–S48.

Harpaz, Dorin & Yeo, Loo Pin & Cecchini, Francesca & Koon, Trish & Kushmaro, Ariel & Tok, Alfred & Marks, Robert & Eltzov, Evgeni. (2018). Measuring Artificial Sweeteners Toxicity Using a Bioluminescent Bacterial Panel. Molecules. 23. 2454. 10.3390/molecules23102454.

Killer, S. C., Blannin, A. K., & Jeukendrup, A. E. (2014). No evidence of dehydration with moderate daily coffee intake: a counterbalanced cross-over study in a free-living population. PloS one, 9(1), e84154.

Alexander, S. (2018). Melatonin: Much More Than You Wanted To Know, Slate Star Codex
Profile Image for David Rubenstein.
804 reviews2,536 followers
March 16, 2019
I love reading science books that are well-written by an author who is really an expert in the field. And, in this case, Dr. Satchin Panda definitely fits the bill. He is a professor at the Salk Institute of Biological Studies. His specialty is the molecular mechanism of the biological clock and the part it plays in overall health. On the other hand, I do not care for self-help books written by scientists, and while there is some excellent advice here, there is also some bad advice.

The basic idea here is TRE--Time Restricted Eating. Dr. Panda's excellent advice is to restrict your eating to a 12-hour window. In fact, 10 hours is better, and 8 or 9 hours is optimal. When you are eating, your body is in a fat-making mode. Your body cannot burn fat at the same time as it makes fat. So, in order to burn fat, you should open up your window of abstaining from eating to as long a period as possible. Even a tiny snack in the evening will cause a delay in the fat-burning process. And, if you eat at random times throughout the day and night, then the fat-making process stays on all the time.

So, this advice seems very worthwhile, and Dr. Panda relates research that helps to back up his claims. Where he diverges from common sense, is when he suggests that you can eat any type of food you want; the time windows when you eat and don't eat are most important to weight loss. Hmm ... seems like if your concern is to reduce the fat in your body, then restricting fat intake should also be a consideration. Or am I missing something here?

Nevertheless, the author has a lot of very good advice, especially for getting a good night's sleep. He suggests eating a last meal of the day at least two to four hours prior to going to bed. This allows your body temperature to go down about one degree Fahrenheit, which is necessary for sleeping. He also suggests reducing blue light from computers, tablets and smartphones as night approaches.

Dr. Panda also dispels a few myths about circadian rhythms. For example, the belief that people are inherently morning larks or night owls is a myth. There is no genetic connection; it is simply a matter of bad habits that are learned. He describes an anecdotal experiment about camping, when melatonin rose earlier in the evening, without bright lights, allowing a longer and more restful sleep. Another myth is the idea about sleep debt as the reason why we often sleep late on weekends, in order to make up for lack of sleep during weekdays.

Another interesting aspect of the book, is the description of circadian rhythms at the cellular level. You body's cells do not all operate on the same cycle. Cells in different organs of the body each have their own circadian rhythms. They are not equally active throughout the day. They become active sequentially, and it is here where the author's research is particularly insightful.

It was interesting for me to read this book at the same time I was listening to the audiobook, When: The Scientific Secrets of Perfect Timing by Daniel Pink. These two books overlap a great deal. But while Pink's book is about more than circadian rhythms, I much prefer Dr. Panda's book; it is much better researched. Despite this book's shortcomings in the "what to eat" department, the advice about "when to eat" should be taken to heart.
Profile Image for Martin Brochhaus.
145 reviews138 followers
August 6, 2018
I read "Why We Sleep" right before this book and thought it might probably the most important book ever.

Well, this one is a close second! While "Why We Sleep" focuses pretty much only on sleep alone, this book underlines and confirms all arguments from "Why We Sleep" but adds a completely new dimension to it: WHEN we should eat and (to a lesser extend) WHEN we should exercise.

It introduces the concept of Time Restricted Eating (TRE) and while there are a few pages of "good ingredients", it doesn't concern itself too much with WHAT you should eat but focuses primarily on WHEN you should eat.

So you are telling me there is way of life where I can eat whatever I like and be healthier than ever? And it's piss easy to pull off?

Well, it seems like it. I started 10-hr TRE about three weeks ago, using their companion app and thus even contributing to a global scientific study. I lost 10kg while eating steaks and hamburgers almost every day and indeed feel healthier, more focused, happier and more energetic than any day of the past 10 years that I can remember. My skin improved dramatically, I lost all my belly fat but most importantly: I wake up every single day BEFORE the alarm at 7:15am, even on weekends, and feel happy to be alive and energetic to start a new day. I didn't think that I would ever feel like this again.

So yeah: Read this book! It will change your life.
Profile Image for Jahongir Rahmonov.
49 reviews14 followers
October 5, 2018
Very useful book. 4 stars because it could have been written much much shorter. After this book I started practicing 9-hour time restricted eating. What this basically means is that I eat my breakfast (the first meal in the day) at around 8 and I eat the last one at around 5. After that I eat/drink nothing but water. I lost 7kg (down to 78kg from 85) in a couple of months. The most interesting thing is that I didn't stop eating burgers, plov and pizzas.

I am also paying more and more attention to my sleep schedule. Giving myself at least 8 hour sleep opportunity and thus actually sleeping at least 7 hours. Sleeping and waking up at the same time every day. This gives me more energy throughout the day.
Profile Image for Amanda NEVER MANDY.
453 reviews99 followers
August 28, 2018
Step right up, folks! I have a humdinger of a cure for ya that will add years to your life and make you the person you have always wanted to be!!! All you have to do is follow this simple plan…

This book reads like a script from an ol’ timey Medicine Show. The author is the perfect peddler, pimping out his miracle cure for everything that ails you. He preaches to you about how all the things you suffer from are all connected (even if you haven’t realized you had them and that they were actually a problem) and how they can be cured if you change your life and live exactly the way he says to. He teases you with promises and dangles the impossible right before your eyes just like every other salesman trying to get you to buy into the latest and greatest diet and exercise plan.

The basic premise of this book is that a person has to have complete and total control of their circadian rhythm (24 hour internal clock). He tells you all of the consequences (disease, poor quality of life and premature death) and details his plan of action to become master of your own domain. What I found infuriating was the way the author presented it.

Here is his bullshit template:

1) LIE
You can eat whatever you want and as much as you want and you can still obtain your weight loss goals.

You have to limit the hours that you are allowed to eat and you have to make all of these other changes to your life to make this happen because those hours are pretty much the same for everyone.

You really do need to eat healthy and limit the amount you eat because duh, eating large quantities of junk food is bad for you.

He repeats this template over and over again with every change he says needs made to your life.

1) LIE
Adjust your sleep schedule to match your own natural sleep/wake cycle.

You cannot eat before bed, you cannot use electronics before bed, lighting has to be adjusted perfectly and alarms are bad so let your body naturally wake up. Having a job that doesn’t match your sleep/wake cycle is bad so find a new one, but good luck because you also need to get two hours of sunlight first thing in the morning and exercise too. Also, shift work is bad so you can’t have that kind of job either.

Everyone’s sleep wake cycle is actually the same since cave man days so you have to sleep and wake at the same time as pretty much everyone else.

He of course includes examples of success stories and cites his research countless times to back up all of his many claims. His success stories are generic and what he draws from them are biased. A perfect example of this is with the story he told regarding a retired postman. The gentleman in question had lived a happy life until he retired, his health (mentally and physically) quickly declined and he had to seek medical care. The author claims that things only began to improve after he reset his schedule to meet the requirements of the author’s lifestyle plan. He mentions that the doctor (who is a follower of this plan) had the patient wake early to attend a walking group therapy session. What he doesn’t acknowledge is that maybe the group socialization played a part in the improved health of the patient considering his retired lifestyle included never leaving his house or having human interaction.

My complaints with the concepts being presented in this book far outweigh the positives. To me it is a book filled with life changing ideas that are only obtainable if your life is one that doesn’t contain any other responsibilities outside of obsessing over your own health. Life is truly too short to live such a restricted life and whatever years that might be gained from it on the back end are better spent throughout enjoying the random craziness that is living.

Originally I rated this read two stars but the fact that it put me to sleep numerous times, pissed me off and is not a book I would recommend dropped it to one.
Profile Image for Holly.
1,007 reviews220 followers
November 12, 2018
This book is really about TRE (Time Restricted Eating) and the benefits of TRE for health. Weight loss might be a result of restricting one's eating to 12 hours a day (or 11, 10, even 8 for the devoted), but other effects are better sleep, improved digestion, energy levels and athletic performance, etc. We alter our circadian clocks by eating too often - and eating within 3 hours of bed is particularly problematic. Apparently the liver and pancreas (insulin) better accommodate a large meal earlier in the day than the exact same meal at night .... I remember when we were taught that it's simply "calories in, calories out" and that eating small meals= good. New research shows that a true daily "fast" or mini-fasts are important.

Profile Image for Anna Hyclová.
7 reviews1 follower
December 18, 2021
One of those books that you read and immediately really want to share with everyone around you, I’ve been bothering my friends with random facts and tips every day since I started reading. Really clear and easy to implement takeaways tied into explanations of the research behind it. Made quite a few changes to my lifestyle accordingly and am really happy with the results already.
Profile Image for Taka.
684 reviews507 followers
April 10, 2023
Good, but full of fluff--

Basically, this book's gist can be condensed into one page (or shorter, depending on how hardcore you're with minimalism):
-Restrict your eating time to 8-10h (can start from 12h). One surprising fact here for me was that even coffee in the morning counts as the first "bite," as it starts your digestive system working.
-Try to eat dinner early (6 or 7pm)
-Sleep on an empty stomach (very, very important)
-Take care of your exposure to blue light 2-3h before going to bed
-Exercise early in the morning and/or in the evening (before 6pm)
-Peak performance hours are between 10AM and 3PM (another surprise for me, though I seem to vaguely recall reading something about that a long, long time ago)
-A good schedule may be: Hearty breakfast around 8AM, very light lunch around noon or 1pm, then exercise followed by dinner at 6PM
-If you eat dinner late, give your stomach at least 12-13h of rest before the next meal, & if you go to sleep late, make sure to exercise the next day
-Jet lag tips: don't eat at night local time & stick to the local mealtimes (that'll help reset the stomach clock)

And voila! You have it. Once you implement this for at least 12 weeks, you'll see all sorts of benefits, ranging from disease prevention/treatment to weight loss and improvements in cognitive performance. The best thing about this is that TRE doesn't add anything (from a risk/probability point of view, addition is risky when dealing with complex systems like our body with many interdependencies, resulting in unpredictable outcomes)—it just changes when you eat (and subtracts those late night snacks—subtraction is usually a good strategy), so there's no reason NOT to try this.

The rest of the book is either filler or fleshing out those points with research to help you understand the reasons for them. One important complaint I have is that like many scientists, he seems to assume that the human body is a machine and that mental illnesses occur as a result of chemical imbalances. You might benefit from reading Gabor Maté's latest opus, Myth of the Normal for an alternative view that many/most of the mental illnesses we suffer today result from the coping strategies we adopt in our early childhood.

Further, probably due to his machine conception of the human body to the exclusion of human intelligence and choice, as well as to confirmation bias, he makes blanket statements about the importance of the circadian rhythm (e.g., "I believe that most of the diseases that affect us in adulthood can be traced back to circadian disruption" (p. xix)).

If you discount these faults, the book can reward you amply (but I've only started experimenting, so the jury is out, at least for my individual case).
Profile Image for Yelena Dubovaya.
76 reviews6 followers
August 23, 2018
Debated on rating this a 4 or a 5, but given the fact that I've been convinced to try TRE (Time restricted eating - AKA Intermittent Fasting) - I think this deserves a 5.

Overall, an interesting read outlining the benefits of all the basic things I've heard since adolescence (get enough sleep and don't eat after 6pm). However, instead of just preaching these mantras, Dr. Panda goes into detail about the reasoning behind the benefits and what happens on a cellular level - which is both convincing and intruiging.

I also really enjoyed the brief discussion on hospital lighting and the problems patients have sleeping in hospitals because the lights are continually on - I think this is an area that deserves further research as it could be beneficial to patients suffering from various health problems. Circadian cycles could also be useful for scheduling surgeries during times that are closer to promoting cell rejuvenation and could set patients up for quicker healing times and thus a more efficient recovery.

Overall, a lot of great ideas that are engaging and some very interesting research to back up the claims made.
Profile Image for Peter Tillman.
3,627 reviews325 followers
Want to read
July 26, 2018
This sounds unpromising -- I mean, Rodale Press! But the NY Times has good things to say about the idea, and the author is a professor at the Salk Institute and an expert on circadian rhythms research. Dr. Panda argues that people improve their metabolic health when they eat their meals in a daily 8- to 10-hour window, taking their first bite of food in the morning and their last bite early in the evening.

Here's the NYT article :https://www.nytimes.com/2018/07/24/we...
Profile Image for Katie.
125 reviews1 follower
August 31, 2019
Over and over I was floored by the information in this book. I read it slowly, bit by bit, over about 8 weeks, learning as I went. There is so much packed in here, and I'm grateful for Dr. Panda's work to bring together all this science and present it -- I have changed how I eat and am working hard to give myself the sleep I need given my much deeper understanding of its profound effects on the body.
Profile Image for Sean.
39 reviews
August 1, 2018
Some great information here. It just felt like he was padding it a bit to get to book length. He repeatedly states it doesn’t really matter what you eat, but then turns around and spends a significant portion of the book telling you what you should and should not eat. Still, the main takeaways are definitely valuable and actionable. Worth a read.
Profile Image for Kate.
606 reviews516 followers
January 12, 2019
This one was interesting. I took away a couple of things from it for sure, but there was a lot of science-heavy stuff in there that passed me by!
Profile Image for Leo Walsh.
Author 3 books93 followers
March 15, 2020
Satchin Panda is a well-respected scientist, known for researching circadian rhythms in mice. And he is wicked-smart. But THE CIRCADIAN CODE seems to fall a little short for me. Why? Panda generalized his research with mice to humans, perhaps in places where it is not warranted. And this makes him see a CIRCADIAN SOLUTION to nearly every problem facing humans in the 21st century,

Have diabetes, ADHD, depression, high blood pressure, leaky gut, fatty liver, etc? Panda has a solution: go to bed at 10 PM and rise 5:30 AM. Because it's CIRCADIAN.

Need even more help? Eat following your CIRCADIAN rhythm in what Panda calls a Time Restricted Eating (TRE) pattern. TRE means you will eat 100% of your daily calories within the first 10 hours after you wake up. After that, it's nothing but water. So if you wake up at Panda's 5:30 AM recommendation, he'd have you done eating at 3:30 PM.

Because it's circadian. And mice do x? It's all a bit too much for me. Panda obsesses, trying to tie too much into his research, even things that really require more research. What's more, his recommendations will not work for everyone. Most people are at work between most of the hours where our "circadian feeding window" is. I'd say maybe 5% of Americans could follow his schedule.

Gripes aside, though, I know there's something to what he's saying. I know I have an internal clock. I feel focused in the morning and for several hours after my dinner. And I have been following Panda's advice about dimming lights and tinting my PC's screen to the yellow-red color range as the night progresses. What's more, instead of using bathroom light fixtures from about 10:00 PM on, I've been using a very dim nightlight So when I do fall asleep now, the quality of my sleep has improved. I think it's because of Panda's recommendations.

What's more, since New Years, I've been following a resolution not to eat anything after 9 PM. I drink my coffee black and often skip breakfast, so I've been unintentionally following a TRE eating style. And I have lost about 20 pounds. But I think it's more to do with mo late-night chips, popcorn, blocks of cheese or the peanut butter and jelly sandwiches I'm addicted to.

When it's good, which is often, THE CIRCADIAN CODE a pretty good pop-science book marketed towards the health and dieting crowd. But like too many diet books, whether Atkins, Vegan or Paleo, Panda tries to tie EVERYTHING back to his core idea. Which bugs me for some reason.


PS. If you do want a better book that covers more-or-less the same material but from a scientific perspective based on HUMAN experiments, try THE OBESITY CODE by Dr. Jason Fung. I found th ebook better because he focuses specifically on the human metabolic and hormonal pathways indicted in obesity, diabetes, high blood pressure, etc. unlike Panda, who is not a physician. Fung is. So instead of extrapolating from tests on mice, he just focuses on what works... for people.
Profile Image for Milan.
275 reviews2 followers
December 12, 2020
The main idea in The Circadian Code by Satchin Panda is TRE - Time Restricted Eating. According to him, restricting our eating hours could be the key to curbing obesity, kidney disease, high cholesterol, bad sleeping, joint pain, possibly even cancer, according to recent research. This idea seems too far-fetched. The most unscientific thing that he says is "Everyone should focus more on when they eat, instead of what they eat." Still, there were a few things to be learnt from this book:

• Weight loss might be a result of restricting one's eating to only a few hours a day.
• A healthy lifestyle includes what and when you eat, when and how much you sleep, and when and how often you move.
• Once we can adapt to a lifestyle that is aligned with the natural circadian rhythm by maintaining the proper sleep-wake cycle.
• To have a good night’s sleep, we should have our last meal at least 2 to 4 hours before going to bed to ensure that the body is able to cool down.
• Coffee can stay in your system as long as 10 hours.
• Fiber helps detox your body and provides nutrients for a healthy gut.
• Your optimal brain function is highest between 10:00 a.m. and 3:00 p.m.
• Eating at the same time every day is one of the most powerful ways to maintain a regular circadian rhythm.
• If you start your morning activity before breaking your overnight fast, your muscles will spend more energy, using even more fat as the energy source, literally melting away even more body fat.
• Modern lifestyle has created an entirely new type of circadian disruption—a digital jet lag—where our body is in one location, but our mind is operating in another.

The book was did not say anything new in learning about sleep but its good in understanding the natural rhythm of human body and restricting our eating time during the waking hours.
Profile Image for MIKE.
36 reviews13 followers
January 20, 2019
Almost five stars, as I will accept any advice that suggests I can have a terrible diet - and as long as a wrap up my eating to a 8 to 12 hours window a day I will be healthy. Lots of interesting details on the body's circadian rhythm I didn't know - I struggle with poor quality sleep, and have used a simulated dawn wake up light to try to help set my daily rhythm in darker Canadian winters, so it was really interesting to read how much else in the body is driven by it's own circadian rhythm and how we might better benefit those natural rhythms through time restricted eating, sleep, light exposure, exercise.
Profile Image for Simona.
79 reviews17 followers
June 1, 2021
Šiais metais kažkaip skaitau knygas, kurios susijusios su savarankiškos pagalbos ieškojimu. Jei man kas nors būtų pasakęs, kad reguliarių ir suderintų ciklų pagalba susitvarkysiu psichologines ir fizines problemas - tikrai būčiau pirstelėjus iš juoko. Bet paskui skeptiškai raukydamasi pradėjau remtis beveik akivaizdžiais patarimais ir susitvarkiau savo gyvenimą prieš tai svarsčiusi jį gydyti vaistų pagalba. Geriausia kuracija yra savęs įsiklausymas. Kai žmogus negirdi savęs - nejučiomis pasineria į chaosą ir juo tampa. Labai rekomenduoju, gan paprastai ir suprantamai parašyta, didelės filosofijos tame nėra - tik elementarus kūno procesų aiškinimas.
Profile Image for Marko.
2 reviews
September 27, 2018
This book is the attempt of a scientist to make his field of expertise available to the general public. And in a way, this makes it an important book, as this is the first one to summarize all the findings regarding circadian clocks (up to this point) in a way, that allows you to get an overview without having to sift through all the relevant papers yourself.

But there are some problems with this book. For one, in an attempt to make the content more available, the author sometimes makes use of some clumsy examples to fit the current scheme of "popular science books". However, Panda appears not to be as skilled in writing non-scientific texts as some of his more popular colleagues in other fields. Consequently the examples sometimes seem a bit constructed and cheesy.

Another thing that might put some readers off is that Panda does not provide the complete, simple and proven system to make the reader believe in the "circadian code" that he title (and some of the formulations in the text) suggest. I blame this mostly on the fact that he tries to derive a life style from the actual science. But, as the field is relatively young, the studies are far from complete, and he refuses to fill in all the blanks with fabrications (as many of the non-scientific health gurus do). What the reader is left with a collection of sometimes unrelated or seemingly conflicting findings that do not provide one big, coherent picture how to fix all health related problems.

For example, many of the experiments that are cited were conducted on lab rats, not humans. Does this make them irrelevant? Maybe. Maybe not. We can't know for sure until we try. So there are only two options for the author. Either he only uses the studies that are already proven to be relevant for humans. This would make a much shorter read. Or he includes all of them and hopes, that the reader might benefit from them the same way the scientists do: As foundation for further thought and (maybe self-?)experimentation. Panda chose the latter, probably also as a way to convince more people to use his TRE research app as this would allow him to confirm or refuse hypotheses derived from lab rat experiments in humans faster.

I like about the book that you can get good overview of many of the experiments that have been conducted in this area so far and which hypotheses the scientists derived from the results. The according scientific papers are not as easy to read or even legally available for the interested individual at an affordable price.

What i don't like are the occasional attempts to fit the self help / magic-diet / wonder cure type of books, which do the content no favor. The constructed(?) examples actually made the book less approachable for me.

Personally, i would have preferred a version of this book that explains all of the experiments in laymen's terms, discusses the findings and derived hypotheses in a neutral way and stays away from overstated promises and cheesy constructed examples. Until this books comes around, the Circadian Code is the best option for the interested layman on a time budget.
Profile Image for Nigeyb.
1,209 reviews266 followers
September 5, 2018
As I age I have found it increasingly hard to stay asleep. I nod off within 10 minutes however tend to wake up sometime between 3 and 5 am and struggle to get back to sleep. Consequently I have developed a keen interest in books and advice about sleep.

This one is well worth a read if you have an interest in sleeping better or, more broadly, optimal health. As with many such books it contains a lot of extraneous detail and is a bit repetitive however Dr. Satchin Panda's pioneering work is fascinating.

I was stunned to discover that the Circadian rhythms, which control our genes at different times of the day or night, operate at a cellular level.

Dr. Satchin Panda helpfully explores the implications of his research and how virtually everyone could benefit by making fairly simple changes. The main takeaways for me were the power of time restricting eating (eating all calories within an 8-10 hour window), trying to stick to a consistent sleep schedule which mirrors nature, and - almost inevitably - the power of exercise.

Profile Image for Ivan.
671 reviews122 followers
January 16, 2022
I learned about this book through Andrew Huberman, a Stanford neuroscientist. Ordinarily, grandiose titles like this put me off, but this was exceptional and I’m already putting much of it into practice.
Profile Image for Blackdogsworld.
66 reviews12 followers
July 20, 2018
ในที่สุด ผมก็อ่าน The Circadian Code จบจนได้ ใช้เวลาอ่าน 10 วัน อ่านวันละนิดหน่อยเท่าที่พอมีเวลา หากลดเวลาเล่นเฟซบุ๊คลงก็น่าจะอ่านได้เร็วกว่านี้ แม้จะเก็บรายละเอียดได้ไม่หมด แต่ผมคิดว่าตนเองได้ประโยชน์จากการอ่านพอส��ควร

ใจความหลักของหนังสือเล่มนี้ อาจสรุปได้ว่า ดำเนินชีวิตให้สอดคล้องกับนาฬิกาชีวภาพของร่างกาย โดยกินให้เป็นเวลา นอนให้เพียงพอ ออกกำลังกายให้พอเหมาะ และโดนแสงสว่างให้พอดี

ดูเหมือนจะเป็นหลักการที่เข้าใจได้ไม่ยาก และทุกคนก็น่าจะทราบกันดีอยู่แล้ว แต่ไม่รู้จะทำยังไงมากกว่า

สิ่งที่ผู้เขียนเน้นย้ำมากที่สุดคือ การกิน ด้วยแนวทางที่เรียกว่า Time-restricted eating (TRE) คือการกำหนดช่วงเวลาในการกินและการงดอาหารให้ชัดเจนในแต่ละวัน โดยงดอาหารให้ได้อย่างน้อย 12 ชั่วโมงขึ้นไป

เช่น งด/กิน 12/12, 14/10, 16/8, 18/6 (หน่วยคือ ชั่วโมง) เป็นต้น

จากประสบการณ์ส่วนตัวของผมที่ใช้สูตร 16/8 ในการกำหนดช่วงเวลาในการกินและการงดอาหาร ทำให้ปริมาณแคลอรี่ที่ผมได้รับในแต่ละวันลดลงไปโดยอัตโนมัติ เพราะงดการกินมื้อดึก ช่วงเวลาในการงดอาหารที่มากพอ ทำให้ร่างกายเผาผลาญไขมันได้มากขึ้น นำมาซึ่งน้ำหนักตัวและรอบเอวที่ลดลง

หากใช้ประกอบกับหลักการเรื่องแสงสว่างด้วยก็จะยิ่งช่วยเสริมให้แนวทางมีประสิทธิภาพมากขึ้น นั่นคือ ให้กำหนดช่วงเวลากินอาหารภายให้อยู่ในเวลาที่มีแสงสว่าง เพราะเป็นช่วงเวลาที่ระบบย่อยอาหารทำงานได้ดีที่สุด เมื่อเข้าสู่กลางคืนระบบนี้จะทำงานลดน้อยลง ทำให้การย่อยและการดูดซึมสารอาหารไม่มีประสิทธิภาพ

เช่น เริ่มก��น 06.00 น. งดกินหลัง 18.00 น. (12/12) หรือเริ่มกิน 08.00 น. งดกินหลัง 18.00 น. (14/10) หรือเริ่มกิน 10.00 น. งดกินหลัง 18.00 น. (16/8) เป็นต้น

แนวทางนี้ผมยังไม่ได้ทดลองครับ เพราะผมเริ่มกิน 12.00 น. และงดกินหลัง 20.00 น. ซึ่งตอนนี้เป็นแนวทางที่ลงตัวที่สุดสำหรับผม

ผู้เขียนระบุว่าเพียงทำตามแนวทางนี้ก็ช่วยให้สุขภาพดีขึ้นได้มากแล้ว เพราะมันช่วยไปปรับนาฬิกาชีวภาพในร่างกายให้ทำงานเป็นปกติ ปัญหาด้านสุขภาพ���องส่วนใหญ่เกิดจากการที่นาฬิกาชีวภาพทำงานผิดเพี้ยน ซึ่งก็เกิดจากการมีวิถีชีวิตที่ไม่สอดคล้องกับธรรมชาติ

ในหนังสือเล่มนี้ ผู้เขียนอธิบายกลไกทางสรีรวิทยาที่อยู่เบื้องหลังไว้อย่างละเอียดด้วยว่า เพราะอะไรเราจึงควรกินให้เป็นเวลา นอนให้เพียงพอ ออกกำลังกายให้พอเหมาะ และโดนแสงสว่างให้พอดี แต่ผมไม่มีปัญญาพอที่จะสรุปสั้น ๆ ให้เข้าใจได้ จึงแนะนำให้หามาอ่านกันครับ
Profile Image for Piotr Karaś.
202 reviews7 followers
February 23, 2021
I loved this book. My key take-away is: start your breakfast at about the same time every day, because your first bite of the day triggers all the digestive organs to start their circadian cycle. The book contains a lot of other useful advice, worth remembering, if you care about your health and your healthspan.
Profile Image for Petra Lazárková.
99 reviews12 followers
April 28, 2021
Choďte spát brzy a ve stejný čas. Nepijte alkohol a nejezte před spaním. Taky nečučte do mobilu. Tak, právě jste hacknuli svůj cirkadianni kód 🤟
This entire review has been hidden because of spoilers.
Profile Image for Jack Reid.
241 reviews10 followers
May 11, 2021
This book is a mixed bag. Dr. Panda opened my eyes to the circadian rhythm affecting our diets. But, he also offers such terrible advice on diet that I'm wondering if the food lobby backed his research. Further, like many books by specialists, the short book suffers from bloat. I'll cover each of my takeaways in the following paragraphs but can't rate above 2-stars.

Circadian rhythm is important. Dr. Panda has dedicated his career to studying it and provides the most in-depth review I've read of the subject. The book explains that different cells within each organ follow their own rhythm. The prose is easy to read and written for a layman like myself. Key takeaways:

1. time-restricted eating, defined as eating in an 8-12hr window each day, is optimal for health.
2. start eating in the morning within an hour of waking up and finish between 2-4hrs of sleeping
2. wakeup with sunrise (optimum) and get 7-8hrs of sleep

The takeaways are easy to understand and make sense. I imagine our hunter-gathering ancestors operated similarly. There's more analysis and takeaways but I believe these are the cornerstones of Dr. Panda's research. All good so far.

However, Dr. Panda falls into the whirlpool affecting many specialists' works. He believes that following your circadian rhythm will solve all problems. He goes as far as to say, "everyone should focus more on when they eat, instead of what they eat." He also cites studies indicating TRE is more important than diet in mice. But, he qualifies his statement with a short blurb on what to eat (which is quite good). By offering advice on eating in such a manner, he adds to the confusion surrounding diet, nutrition, and exercise.

Frankly, I skimmed the entire third section where Dr. Panda ties circadian rhythm to every disease known to man. According to the good doctor, ADHD, diabetes, cancer, and more can be prevented and treated by following your circadian rhythm. He gives short examples after each strong statement from his private practice. Pardon my skepticism, but I can't imagine eating an American diet and following your rhythm will cure all ills. Hence why I skimmed the section. It reads like a specialist - pull out all the studies linking your specialty to positive outcomes and overwhelm the reader with data. Then, they'll believe you.

To conclude, circadian rhythm is an important topic and I learned plenty from reading Dr. Panda's book. But he offers a lot of conflicting information and offers his discipline as a panacea to all health problems. And I can't stand for a book that illustrates the world in such black and white.
Profile Image for Andreas.
624 reviews37 followers
March 11, 2020
There are things that you know but not really follow until you learn how important they are. Drinking enough water comes into my mind, eating more vegetables, exercising and so on. Getting enough sleep and following your inner clock is one of these topics and this book opened my eyes.

The author makes a strong argument that modern life interrupts our inner clock with drastic consequences. Not immediately but when we get older the body may start to break down showing diseases that are all too common now. He backs this up with a lot of science and I must say: I am convinced.

There are many details and I highly recommend the book to everyone who is interested in longevity.

The good news is that you can get back into a healthy circadian rhythm rather quickly and I am currently experimenting with it. The easiest things to follow are:

- no exposure to light before going to bed (e.g. no electronic devices 1-2 hours before bedtime)
- the time you eat

The 2nd point was very interesting. When you eat something your organs must get ready to process the food and they stay up for another 3-4 hours. This means that a late night snack, let's say some chocolate at 22:00, will keep your organs up until 2:00 and only then the body can start with the recovery and cleanup.

The author proposes a reduced window of 8h during which you can eat whatever you want (drinking water is fine). I am really curious how this will work out because now I have a window of 12-13 hours. Stay tuned for an update in the next months!

Highly recommended
Profile Image for Two Readers in Love.
550 reviews15 followers
August 28, 2018
While it is a bit repetitive in parts (or, to be fair, perhaps I'm just too sleep-deprived to absorb the underlying organizational structure?) this is quite a useful book. I've been reading multiple books on sleep this year, and this one covered some similar ground but also introduced several areas of research that were entirely new to me. Dr. Panda's research is on the multiple interrelated clocks in our body, so whereas most of the popularization of the research that I've read so far focuses on the brain's hypothalamus and the suprachiasmatic nucleus and the relationship between sleep and learning, this book also presents some of the system-wide relationships between sleep/wake and digestion, immunity, and the body's clock(s).

This is also the first book that gives a really detailed plan of practicalsteps you can use to improve your circadian rhythms, especially if you are not a retired, single, multi-millionaire who has the resources to adhere to the sensible but impossible-to-follow "stick to a fixed bedtime" rule. I am skeptical that the timing of food will actually result in all the large-scale benefits promised in the book - then again, at this point in our culture, any nutrition advice provided by a self-help books can't help but seem a bit faddish - but for an n=1 experiment, I'm looking forward to taking a deeper dive and trying the mycircadianclock.org app.
3 reviews
December 10, 2021
I'm a bit torn because yes, the main advice is good which is:

1) Eat breakfast, dinner and preferably lunch at the same time every day
2) Don't snack outside meals and especially after dinner

But that's basically it. The rest is filler with studies based mostly on mice and sharing recommendations on topics that the author doesn't seem to have much practical knowledge about such as exercise and diet. There was clearly a lot of things that sound good in theory, but are way oversimplified. However, the author re-re-re emphasises how important points #1 and #2 are so they do get stuck in your head enough that you will reconsider your lifestyle in a positive way.

tl;dr: circadian clock stuff is good, backing of the theory is bit dubious and the part on nutrition and some things on exercise are oversimplified / unproven / inaccurate. Possible to implement a positive change in anyone's life after reading the book especially to timing of eating
Profile Image for Shreeram.
16 reviews5 followers
March 6, 2022
A wonderful book on maintaining a good lifestyle. This book was a light read to me as I was familiar with the concepts the author was explaining but the book was engaging and informative until the end.
Profile Image for Amelia.
Author 9 books83 followers
December 19, 2019
Meh. I was disappointed in this one. It's got some good points but it boils down to two or three general recommendations:
1. Expose yourself to bright light during the day and use only task lighting at night.
2. Eat during an 8-12 hour window, ideally during daylight hours.
3. Those two things should help you sleep better and maintain circadian rhythm of other organs (gut, brain, liver, skin, etc.) for optimal health.
There's a lot of filler and too much emphasis on weight loss for my tastes here. I was hoping for more when it came to optimal time for exercise and mental work. Also there was virtually no discussion of different chronotypes, which I found a serious shortcoming.
Profile Image for P.S. Carrillo.
Author 4 books11 followers
June 17, 2018
Excellent research on a topic that should be a part of every medical doctor's prescription pad. I first became aware of Dr. Panda while watching Dr. Rhonda Patrick on YouTube. It was a fascinating interview and based on the science presented I went on a time restricted eating regimen immediately. That was over 1 year ago. Better overall health, digestion, weight control, sleep, etc. Than you Dr. Panda for all of your hard work. The human body continues to astonish.
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