Entraining Central and Peripheral Circadian Rhythms

“Desynchronization between the central and peripheral clocks by, for instance, altered timing of food intake, can lead to uncoupling of peripheral clocks from the central pacemaker and is, in humans, related to the development of metabolic disorders, including obesity and type 2 diabetes.”

If you haven’t been following along, a few papers came out recently which dissect this aspect of circadian rhythms — setting the central vs. peripheral clocks.

In brief (1):  Central rhythms are set, in part, by a “light-entrainable oscillator (LEO),” located in the brain.  In this case, the zeitgeber is LIGHT.

Peripheral rhythms are controlled both by the brain, and the “food-entrainable oscillator (FEO),” which is reflected in just about every tissue in the body – and is differentially regulated in most tissues. In this case, the zeitgeber is FOOD.

In brief (2):  Bright light in the morning starts the LEO, and one readout is “dim-light melatonin onset (DLMO),” or melatonin secretion in the evening. Note the importance of timing (bright light *in the morning*) – if bright light occurs later in the day, DLMO is blunted: no bueno.

Morning bright light and breakfast (FEO) kickstart peripheral circadian rhythms, and one readout is diurnal regulation of known circadian genes in the periphery.  This happens differently (almost predictably) in different tissues: liver, a tissue which is highly involved in the processing of food, is rapidly entrained by food intake, whereas lung is slower.

Starting the central pacemarker with bright light in the morning but skimping on the peripheral pacemaker by skipping breakfast represents a circadian mismatch: Afternoon Diabetes? Central and peripheral circadian rhythms work together.  Bright light and breakfast in the morning.

 

 

 

Exhibit A. The world’s most obvious study: regulation of the central pacemaker and its impact on circadian phase (Burke et al., 2013).

 

bright light melatonin

 

After a variety of baseline measurements, researchers exposed volunteers to 1 of 4 conditions, and assessed dim light melatonin onset (DLMO), a readout for central circadian rhythmicity. The conditions: Bright Light in the morning (BLP), Melatonin a few hours prior to bedtime (DLM), Both (BLM), or Neither (DLP). As expected, no light in the morning and no melatonin at night (DLP) = circadian phase delay (ie, can’t fall asleep at night & groggy in the morning).  Bright light in the morning and melatonin at night (BLM) = circadian phase advance and better sleep quality.  Capiche?

 

Optional background reading on the role of diet in controlling circadian phase.

 

Exhibit B. One of the most popular studies on circadian biology this year (Chang et al., 2014)

Night time exposure to artificial light, smart phones, laptops, computers, TV, etc. knocks the wind out of the central pacemaker.  It is the antithesis of bright light exposure in the morning.

These researchers gave their participants a paperback book or an e-Book (eg, Kindle or smart phone) to read in bed at night.

 

e-Book reader

 

^^^ BOOM! (P<0.05)

 

Exhibit C. Similar to breakfast (in the morning), the AM cortisol spike (ie, Cortisol Awakening Response) also contributes to setting peripheral circadian rhythms.

This study garnered almost as many headlines as the e-Book study, but I think it was somewhat misinterpreted (surprise, surprise).  As mentioned above, DLMO is a readout of circadian phase and a healthy central pacemaker.

In this study, participants were given a cortisol precursor drug in the afternoon (out of phase) to see if it could entrain the central (ie, DLMO) or peripheral (diurnal regulation of circadian genes in the periphery) pacemakers.  As a surrogate for the peripheral pacemaker, they measured rhythmicity of circadian genes in blood cells (monocytes).

They showed that, interestingly, a cortisol spike in the afternoon didn’t feed back into the central pacemaker (ie, there was no change in DLMO), but did feed forward into the peripheral clock.  Eating breakfast in the morning is a  [better*] way to entrain the peripheral circadian clock.  I say “better” because spiking cortisol in the afternoon was a trick used by the researchers to test the hypothesis, not the physiologically appropriate Cortisol Awakening Response.

The central and peripheral pacemakers are, to a degree, independently regulated. Bright light exposure (in the morning) and avoidance of bright light (at night) are better at entraining the central circadian clock, and food intake is better at entraining the peripheral clock… to synchronize all clocks: breakfast & bright light in the morning, and avoidance of bright light at night.

 

“Desynchronization between the central and peripheral clocks by, for instance, altered timing of food intake, can lead to uncoupling of peripheral clocks from the central pacemaker and is, in humans, related to the development of metabolic disorders, including obesity and type 2 diabetes. ” (Oosterman et al., 2014).

 

 

Tangents (1): I know what you’re thinking: “Bill-man, some aspects of Low Carb are similar to fasting, like low insulin levels.  Given this, are bacon & eggs really an adequate stimulus for the FEO?”
To which I’d respond: Researchers have been searching for YEARS, for the biological location and/or precise hormonal stimulus that entrains the FEO.
They haven’t found it.
It’s not insulin: FEO is intact in type I diabetes.
Not everything is regulated by insulin.
disappointed?   😛

Tangents (2): Prolonged fasting blunts peripheral circadian rhythms (get it? no food intake, no FEO); thus, if you engage in intermittent fasting, the duration and frequency should be carefully considered.  In this regard, a consistent, regular pattern of intermittent fasting could desynchronize the central and peripheral clocks, depending on the duration and frequency… a crude translation of this: bright light but no food in the morning, combined with the opposite at night = circadian desynchrony via mismatched LEO and FEO.  To be clear, some degree of fasting is probably good for you, but should be timed with darkness, at night (when you should be sleeping or at least winding down; getting ready for bed).

Body temperature is another input into circadian rhythms.  It declines at night. Wanna throw a wrench into this gear?  TEF. (not as bad as artificial light at night, just sayin’)… also, this might be another reason to avoid exercise at night (HT/ Chimbo).

These are not mouse studies!  See the many human studies on circadian desynchrony, discussed here:

Skipping meals, intermittent fasting, grazing, etc.

and

“Afternoon diabetes” and nutrient partitioning

 

People love skipping breakfast and will condemn any science which says this behavior might not be optimal, or just say it doesn’t matter.  I know this.  Sorry.

 

calories proper

 

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  • Santino Corleone

    Hey Bill,

    thanks for these articles. I always used to have breakfast. But I the last month I used to just have a coffee with 40g of Ghee. So I get 360kcal, but just from fat with some caffeine.

    Will this be enough to trigger the desired response? You say that they did not find the trigger yet, but maybe they know that fat alone is not enough?!

    I think I should do everything possible to get “into rythm” because of bipolar disorder…Starting my day with this coffee feels good for me. By the way, I am on a ketogenic diet since three months which also lead to more stability.

    But maybe over time I will reintroduce some carbs in the evening like Dave Asprey describes in his Bulletproof diet book.

    Best regards,
    Santino

    • Collectively, the data suggest that more calories earlier in the day is better… 360 kcal is quite low (and no protein?);
      >50% of the day’s calories would be more on par with the studies I’ve seen (big breakfasts almost always trump big dinners, when compared directly).

      • Santino Corleone

        Thanks for your answer Bill.

        Yes. I do this since reading “the bulletproof diet”- book.

        I feel better with less protein (don’t know why). But I eat most calories from fat. Mostly with lunch and dinner, I eat protein.

        So is it necessary to use protein in the morning for circadian rythms? And if so, what would be enough? Would it be enough if I use 10g whey in my coffee? On the other habd protein leads to insulin response and blood sugar risikg in the morning. I felt that I could goncentrate best whole morning when I just use fat and coffee.

        I have so many problems with intolerances, allergic like responses etc. it is not easy for me to find a good breakfast. Eggs and bacon on a regular basis seemed to trigger sone symptoms…

        • “So is it necessary to use protein in the morning for circadian rhythms”

          As mentioned in the post, the precise factor isn’t known, although I’d say a little protein in the morning is prudent (and healthy). It doesn’t have to be bacon & eggs or whey protein — find something that works for you.

          • John

            Besides the inconvenience of modern life I’m skeptical on an evolutionary basis of a full breakfast with protein in the morning. Until the neolithic, perhaps.

          • There are many *modern* RCTs supporting this. Eg, http://caloriesproper.com/afternoon-diabetes-and-nutrient-partitioning-2/

          • Joshua

            My thoughts on morning. Could the window of time for “morning” be proprtional to the amount of daylight. Eg 8 hours in winter vs 12 in summer (depending on location). In the summer your morning is going to have roughly an extra 1.4 hours in it compared with winter. We might want to look at partitions and timing wrt this.

          • 1) get as much sunlight in the morning as possible.
            2) rotation of the Earth around the Sun takes care of the rest.

          • John

            Bill,
            Not if one’s insulin resistant. You said so yourself.
            I’m much better off minimizing the production of both insulin and glucagon and let the glucose level drift.

          • “Not if one is insulin resistant. You said so yourself.”

            The diurnal changes in glucose tolerance are *blunted* in insulin resistance, not reversed. And these are the people who will likely benefit the most from properly entraining their circadian rhythms.

            “I’m much better off…”

            I won’t argue against your “n=1”
            — if you found what works for you, keep doing it!

          • John

            True about n=1.
            Based on the rate of mitochondrial mutation ‘n=1’ experiment carries more weight for one well past middle age.
            Anything and everything sort of work in your twenties.

          • Jack Kruse

            Glucagon is a bigger deal today than most realize. Taubes has gotten everyone on the IR train but he has missed some interesting work that guys like Guyenet have murdered. https://www.youtube.com/watch?v=VjQkqFSdDOc

          • Jack Kruse

            Reality is that which, when you stop believing in it, doesn’t go away.

          • John

            Taleb says it best (Antifragility; p479) when conflict arises between Nature and science:
            “If there is something in nature you don’t understand, odds are it makes sense in a deeper way that is beyond your understanding. So there is a logic to natural things that is much superior to our own. Just as there is a dichotomy in law: ‘innocent until proven guilty’ as opposed to ‘guilty until proven innocent’, let me express my rule as follows: what Mother Nature does is rigorous until proven otherwise; what humans and science do is flawed until proven otherwise.”

          • I like a lot of the concepts in Antifragility, but I don’t think this aspect of physiology qualifies as: “something in nature you don’t understand”
            — the data are there, and fairly consistent.

          • John

            Bill – that comment is fairly tangential to the topic – directed only at Kruse’s comment regarding science as reality.
            I’m fairly well-versed in hard science but would hesitate to lump ‘nutritional science’ into the same class as physics and biology.
            In my original comment I consider it implausible for HG (paleolithic man) to have breakfast with protein – we’re talking about meal frequency and timing here; my style of eating is in no way ‘paleo’ as popularly defined – hence the skepticism.

          • Gotcha.

            The way I see it, there were a LOT of different HG tribes that varied geographically and over time — how sure are you that none of ’em had a protein-rich breakfast in the morning? …could’ve been leftovers from yesterday’s hunt, for example.

            Also, this: http://disq.us/8lzkt2

          • Jack Kruse

            Most HG shows they ate one meal a day…….and this brings IFing and the crafting a small dense microbiome that makes a ton of H2 from prebioic fibers make a ton of sense. The key is the scarcity signal for FIAF for leptin biochemistry without the drive of appetite. Protein simulates this best in this modern world because of how mitochondrial signaling works. They key is understanding the origins of thermodynamic coupling in our mitochondria and then adding to the complexity what happens when you step back in time for your diet while the modern world has taken three steps forward………that is why protein in the AM matters now in a big way. The world 2 million or 100K years ago no way simulates 2015 anywhere on this planet. This is the paleo delusion.

          • Gerard Pinzone

            The advice should be based on what actually works, not whether or not it conforms to a theory or model of reality. https://www.youtube.com/watch?v=b240PGCMwV0

          • ^^^ this.

          • Jack Kruse

            Leptin Rx 101. I tell you why in several blogs.

        • Chad W

          You could consider totally ditching the morning coffee too (can hear the screams)……..It’s smashing your adrenals which can in some cases be related to hypersensitivities…..if your system is in a constant fight or flight mode exacerbated by coffee maybe it makes other systems (for example immune system) hypersensitive and over reactive.

    • “I think I should do everything possible to get ‘into rythm’ because of bipolar disorder”

      yes, definitely!

  • TechnoTriticale

    re: … avoidance of bright light at night.

    Avoidance of BLUE light at night, at any intensity higher than starlight at the eye.

    The recently rediscovered “intrinsically photosensitive retinal ganglion cells” (ipRGCs) contain melanopsin, a photopigment with a sensitivity peak in the 460 to 484nm range (blue, matching skylight almost exactly). Stimulate these, and melatonin production plummets.

    This kind of blue wasn’t all that common in the home prior to the CFL and LED (not to mention large TVs and various flat panel displays, and their “cool” icy blue indicator LEDs). It is now.

    The solution, other than not using such devices, and changing out all the lights for Philips Hue bulbs, is to wear effective blue blockers in the evening (UVEX S9133X, or, with glasses, S0360X). Cheap on Amazon.

    A book on this topic claims, with a cite, that blind women have half the breast cancer rate of sighted women. That’s a material risk, and if the bright and/or blue light at night problem is the trigger, it means that diet and biome aren’t the only things that need to get a lot more paleo.

    • “diet and biome aren’t the only things that need to get a lot more paleo”

      ^^^ epic

      • F.Lux & Twilight are pretty good apps to reduce blue light from smart phones, computers, etc.

        • TechnoTriticale

          In general, apps like f.lux only work to full effectiveness on mobile gear with OLED panels and other display techs where the basic generation of raw light is controlled (plasma, CRT).

          With typical backlit LCD (including “LED” TV), the gating pixel cells, including blue, when fully “off” still let a lot of light leak through. The backlight is usually a full bright white (with a nasty blue peak) at all times.

          And f.lux does nothing for blue indicators on the bezel.

          Wear blue blockers, as I am right now, working with my spiffy new AVA+ LCD monitor. In fact, except when doing critical color work, I wear the BBs all the time when facing such screens, due to the separate “blue light hazard” problem (macular degen).

          As displays with wide gamut start to become more common, it turns out that doing that with mere tri-stimulus color primaries comes with some oopsies.

          • I don’t recommend F.Lux &/or Twilight by themselves. Always BBs first, because blue light comes from more places than your tech screens.

          • Man

            Well, something else I recommend: avoid the PC, laptop, tablet and other screen devices after sunset. No internet, no useless activities in front of a screen: it frees a lot of evening time. These days, I usually light a candle or two, and grab my acoustic guitar after dinner (when I am not grabbing my wife 😉 ).

          • TechnoTriticale

            re: … avoid the PC, laptop, tablet and other screen devices after sunset.

            So easy a caveman could do it 🙂

            People just need to know what the relative risks are, and the effectiveness of various remediation options. The vast majority have no clue there’s a problem lurking, even after it develops into a sleep disorder, endocrine disaster, cancer, etc.

      • Jack Kruse

        Nice to see others getting the larger message.

  • Zach

    What does your eating window look like, Bill? I assume you try to avoid food when the sun goes down?

    • It varies pretty widely, primarily because I’m healthy — not treating any underlying conditions.
      In general, I think the more serious your condition, the more you should consider adhering to better good dietary/lifestyle habits…

  • Jack Kruse

    Keep dropping knowledge bombs Bill. People hate the truth that shows them their current beliefs might be dead wrong.

    • This. “It starts with circadian biology.”

  • Kasha

    I’ve been asking this question for quite a while now without getting any straight answers: When are people with Non-24 supposed to eat? Meal times can either travel around the clock or try to stay within a 12 hour window. Which one is going to lead to gaining weight?

    • Hi Kasha,
      In general, bright light & more calories upon wakening (whenever that happens to be). Avoid bright light & opt for a smaller meal prior to bedtime (whenever that happens to be).
      Big meals and bright light prior to bedtime = no bueno.

  • rs711

    A lot to think about here.

    How would the LEO & FEO affect cytoskeletal build/tear down rhythms? What does p53 et al. think of all this orchestration? Nightshift work and cancer come to mind…

    • Night shift work: light boxes, blue blockers, and proper circadian meal timing are band-aids on a wound that needs stitches.

      Not something I’d recommend doing long-term: http://www.ncbi.nlm.nih.gov/pubmed/25576495

      • Woody Payne

        That article is apparently discussing rotating shifts. That’s different from straight nights, where workers always work nights, follow the same routine on their days off, and aren’t asked to work day shifts. That gives your body a chance to actually adapt. Which can take anywhere from a week to a month. Most people switch back to a more socially acceptable schedule on their days off, and never really adapt. They stay in a half adapted state, with all the bad things that come with that.

        Granted, I imagine there are some things that you won’t get on a strict night shift lifestyle. But I don’t know what those woud be besides all the trouble saved by not fighting nature. If you can simulate LEOs, FEOs, ensure proper temperature control, ensure proper activity control, and have a social life, then what else is there to entrain, exactly?

        • I understand your point about rotating vs. straight shifts, but am not sure to what degree the risks would altered.

          “then what else is there to entrain, exactly?”

          Hehe — I wouldn’t assume we know the whole picture.

  • Dr Josh Lamaro

    cool blog, echoes jacks leptin reset, and reminds me of another circadian discussion i think from here talking about carbs (if at all) only in the AM. blue light laden food electrons with blue light photons. nice.

  • Is the food-entrainable circadian oscillator in the digestive system?

    http://onlinelibrary.wiley.com/doi/10.1034/j.1601-183X.2003.00005.x/full

    Food-anticipatory activity (FAA) is the increase in locomotion and core body temperature that precedes a daily scheduled meal. It is driven by a circadian oscillator but is independent of the suprachiasmatic nuclei. Recent results that reveal meal-entrained clock gene expression in rat and mouse peripheral organs raise the intriguing possibility that the digestive system is the site of the feeding-entrained oscillator (FEO) that underlies FAA. We tested this possibility by comparing FAA and Per1 rhythmicity in the digestive system of the Per?1-luciferase transgenic rat. First, rats were entrained to daytime restricted feeding (RF, 10 days), then fed ad libitum (AL, 10 days), then food deprived (FD, 2 days). As expected FAA was evident during RF and disappeared during subsequent AL feeding, but returned at the correct phase during deprivation. The phase of Per1 in liver, stomach and colon shifted from a nocturnal to a diurnal peak during RF, but shifted back to nocturnal phase during the subsequent AL and remained nocturnal during food deprivation periods. Second, rats were entrained to two daily meals at zeitgeber time (ZT) 0400 and ZT 1600. FAA to both meals emerged after
    about 10 days of dual RF. However, all tissues studied (all five liver lobes, esophagus, antral stomach, body of stomach, colon) showed entrainment consistent with only the night-time meal. These two results are inconsistent with the hypothesis that FAA arises as an output of rhythms in the gastrointestinal (GI) system. The results also highlight an interesting diversity among peripheral oscillators in their ability to entrain to meals and the direction of the phase shift after RF ends.

  • These are some of the concepts that are being discussed in a course about circa rhythms that I’m taking at a German University. It’s pretty much in light with very current research. Everything is so complex. Yet, evolutionarily it seems to fit in…

  • Frances

    Would you happen to know how all this relates to circadian rhythm disorders such as Delayed Sleep Phase? What I mean is… Is “circadian mismatch” always in relation to the normal “get up in the morning, go to bed at night”, or is there such a thing as a circadian mismatch to your own chronotype? Are there even “different” chronotypes, or just healthy vs diseased?

    I’ve got it all by now – blue blocker goggles at night, modafinil and blue LEDs in the morning, a ketogenic diet… I try melatonin here and there, but the smallest effective dose still makes me even more groggy throughout the day, and while it is much easier to fall asleep, it becomes that much harder to wake up.

    Still have major trouble adjusting to a normal schedule. Still perfectly happy to sleep in ranges such as 6AM to 2PM. Still have to force myself to eat breakfast, which feels like a lump in my stomach for a while. And, well, with studies like this I wonder if I’m somehow fooling myself, but I find that I am much healthier, happier, and more productive during the times that I can stay up and sleep in.

    It leaves me wondering… and this is my main question… Is this because I haven’t fully adjusted, and really need to force myself to get a few no-slip-up weeks in a row to get to a normal sleep schedule? Or could forcing myself to sleep and eat like most people in fact predispose me to the same kinds of health problems that most people would experience working long-term night shifts?

    Concentration-wise, fatigue-wise, general health-wise it feels like the latter. But that’s still attributable to plain old sleep deprivation. So I’m still stuck between, on one hand, thinking I’m not trying hard enough to become healthy (and that it’ll all be fine once I can consistently stay in that normal schedule, and fall asleep, and stop sleeping through alarms)… And on the other hand wondering whether this struggle is what’s actually doing the damage.

    I mean, if we’re gonna entertain evolutionary behavior, couldn’t those hunter-gatherers have used some night guards?

    • This is one of the gotchas in circadian rhythm malarkey for me. I dig all the gear going around and read everything Bill and Jack etc post on this stuff, however I’m “naturally” nocturnal, have been my whole life. I mostly understand the circ stuff but everything about me goes against it. I don’t think I’ve slept more than a handful of entire nights sans alcohol.

      Maybe I was one of those guys who were meant to be the night hunter or guard?

      I get super sleepy around both sunrise and sunset, they’re the only times I can reliably put head to pillow and fall asleep without 1-4 hours of random noise going through my head. I’m talking going back 30+ years, this has been the same.

      I even named my geek business “Graveyard Shift” back in the day, because I’m mostly useless during the day, give me 2-3 hours sleep around sunset and once midnight hits my brain and work output is phenomenal, I can do your standard 8 hour day in 1 hour.

      So yeah in the end I’m super interested in all this circadian stuff, but feel I just might be one of those error bar outliers.

      • “Maybe I was one of those guys who were meant to be the night hunter or guard?”

        ever seen anything written on this? [curious]

    • Hi Frances,

      There are bona fide chronotypes, or morning & evening people, but they usually only differ by a few hours.
      Humans are diurnal by nature — all of the science on circadian biology is consistent with this point.

      You might be a night person, but it seems like you’re in a bit of a circadian mismatch right now. Might be worthwhile to figure out the root cause..?

  • Man

    Hey Bill, nice post! I am a breakfast guy now and when I want to IF, I just skip dinner (aka no food after say 4 or 5pm). I do throw occasional ~ 30h fasts but they tend to be rare these days. But when you mention morning bright light, do you include artificial light ? I live in a rather high latitude and even though the sun rises earlier each day, it is still quite dark when I get up from bed (I do use artificial lights at home of course 🙂 ).

    • Thanks!
      In your context, I’d count pretty much all light.

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  • Intake in the morning is associated with a reduction in the total intake for the day, while intake at night is associated with greater overall daily intake. These associations are macronutrient specific, with morning carbohydrate intake associated with reduced daily carbohydrate intake, morning fat intake associated with reduced daily fat intake and morning protein intake associated with reduced daily protein intake. Since different types of foods contain differing proportions of macronutrients, the present study investigated the associations of different types of foods ingested at various times of day with total daily and macronutrient intakes. The intakes of 388 male and 621 female free-living individuals reported in 7 d diet diaries were reanalysed. The intakes of twenty-four different types of foods and seven different drinks occurring during the morning (04.00-10.29 hours), afternoon (10.30-16.59 hours) and evening (17.00-02.00 hours) were identified and related to overall daily intakes. Dairy foods, ice cream, beef, other meats, potatoes, pastry, nuts, chips and snacks, condiments, alcohol and soda were significantly associated with higher total intake over the day, while fruit, soup, breakfast cereal, pasta, pizza, water, coffee/tea and diet soda were either not associated or were associated with lower overall intake. Dietary energy density appeared to mediate the associations between particular foods and beverages and overall energy intake. This suggests that eating low-density foods in the morning and avoiding high-density foods at night might aid in reducing overall intake and may be useful in dietary interventions for overweight and obesity.

    http://1.usa.gov/18SjVtp

  • John-P

    Does anyone
    know if Now-Inulin contains both long-chain and
    short-chain oligofructose? Inulin (mainly long-chain oligofructose), FOS (mainly short-chain oligofructose). Mixture of long-chain and
    short-chain oligofructose supposed to be better. Most of the prebiotics
    do not distinguish inulin and FOS. Now-Inulin presents inulin and FOS as the
    same thing but they are not. I contacted
    Now Foods about their product but I have not got a reply. Jarrow Formulas-InulinFOS clearly specifies
    the content. I wanted to switch to Now-Inulin because it is cheaper per oz and it
    is organic.

    • I don’t know, but I haven’t seen many studies showing: inulin vs. FOS vs. blend…

  • Olga

    Hi Bill,
    Thanks for the post. So if you’re following a paleo-ish diet, with about 70g of carbs per day and you want to reset your clock and improve thyroid function, (while taking iodine, etc.) would it make sense to eat most of those carbs for breakfast when insulin is highest/most sensitive and then eat protein/fat for the rest of the day? Contrary to the notion that carbs late in the day improve sleep. Just trying to sort out all the contradictory information out there.

    • That makes the most sense to me — skewing more calories/carbs in the morning when your body is naturally better at partitioning them into muscle and away from adipose.

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  • jord

    So do you think a good strategy to fix/optimise ones circadian schedule is to do the following:
    wake up with the sun, or at the same time every day,
    get some bright light in your eyes,
    and eat a fat-heavy breakfast within the hour?
    Then have lunch approx 5 hours later (1pm or so).
    Maybe hit a workout 3-4pm, making sure to fully recover and activate the PNS to reduce cortisol etc,
    skip dinner,
    and be in bed approx. 3-4 hours after sunset? (or 10-10:30pm)

    Would love to hear your thoughts on those few ideas!

    • Hi Jord!

      Agree with bright light asap in the morning. But this is the time for protein http://caloriesproper.com/dopamine-and-breakfast/ (and carbs if you’re not LC).

      The research on exercise timing is mixed, but I tend to think it should be timed around meals & protein intake, which should be earlier in the day. Exercise can spike cortisol… we don’t really want this later in the day… but exercise at any time during the day is better than no exercise at all, imo.

      Skipping dinner isn’t necessary, but it should be light, and your least carby meal of the day.

      Not much evidence for optimal timing of dietary fat intake. Ymmv.

      Bedtime a few hours after sunset, rise at dawn, and voila 🙂

      -Bill

      • Jord

        Thanks for your suggestions.
        Excellent articles about circadian cycles and meals/light. Slowly working through them all.

        So with the AM cortisol spike, wont protein/carbs somewhat dampen this?
        That’s the reason I thought fats may be better in the morning, since they wont affect insulin as much.

        Also, is there any danger in consuming a large meal while cortisol is high?

        It almost seems counter-intuitive to wake up alert, then consume a large meal that would potentially slow me down due to digestion etc?

        All this time I thought it was about the fats!
        Damn Bill, seems it’s all about the protonz!

      • jord

        Do you think theres any problem with consuming large AM meal while cortisol is high?
        I once heard a certain JK state it may be best to delay eating a little while to allow the morning cortisol spike to subside before consuming calories; any truth to this?

        Also, whats a reasonable time frame to eat breakfast if the goal is circadian regulation. Wake at 7am, breakfast at 9? Or sooner the better?

        All this time I thought it was about manipulation fats and carbs, turns out it was all about the protonz!

        • I see no reason to delay breakfast — should be timed with light onset to co-entrain peripheral & central clocks.

          • Jord

            When am i ‘supposed’ to exercise then? Preferably after breakfast?

            Do you think it’s more important to time meals with exercise, or light onset?

            ie exercise 1 hour after waking, breakfast after?
            or breakfast first, exercise after?

            I’m speculating exercise is also a zeitgeber, along with food+light. trying to tie them together into a morning routine is perplexing. Any thoughts?

            love your articles by the way. Slowly devouring them all.

          • great questions, Jord.

            Breakfast & light in the morning. Exercise should be around the biggest meals, which should be earlier in the day, so exercise is best timed in the morning.

            ergo, “breakfast first, exercise after”

            If it fits your lifestyle, of course. Exercise later in the day is better than no exercise at all.

          • Jord

            Thanks Bill.
            One last question.. 😉
            if I get up and its still dark, do you think breakfast should still be co-ordinated with sunrise, or waking time?
            For instance, sunrise is approx. 60 min after waking now.
            Any relevance, or much ado about nothing?

            I’m really digging your articles. Some fascinating stuff, particularly about circadian cycles and meal timing etc.

            ps: YMMV?
            TL:DR?

          • Thanks!

            I’d still say to time it with sunrise unless that is a major inconvenience.

  • BullB Man

    Dear Bill,

    As someone who benefits largely from ketosis for brain energy (stable, constant focus), I find myself fit more with the HCLF 23/1 IF dinner protocol. My assumptions:
    The ketones start relatively high in the morning and keep develop through the day, which get my brain fuelled and staying concentrated. Then I exercise in the afternoon and have a big meal that shuts the ketones and rises the insulin for muscle recovery/growth throughout the night (I also tend to get sleepy after the meal and have pretty tight sleeps then).

    Not sure if I understood this properly. I am thinking there might be something misassumed above? What’s your opinion on this?

    • skipping breakfast and having a big dinner can promote circadian phase delay / arrhythmia (like shift work). Might not be the best long-term strategy. Ymmv.

  • Shane

    Bill, what are your thoughts on diet for adrenal fatigue? Should one eat more meals and snacks? What about IF’ing? I’m assuming that entraining circadian rhythms are crucial for recovery? Thanks!