The Pseudoscience of ‘The Circadian Code’
Reviewing Satchin Panda’s book about the Circadian Rhythm
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.
As 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 defence, 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 were 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 bedtime. 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.
That’s it.
Thanks for reading. If you like non-fiction book reviews, feel free to follow me on Medium or subscribe to my Substack.
I also have a philosophy podcast. If you want to check it out look for Anagoge Podcast.
Tiago V.F.
References:
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
