Circadian phase: role of diet

Circadian phase advance: going to bed earlier, waking up earlier.  Blue blockers at sunset, bright light at sunrise.  Flying east.  Autumn.

Circadian phase delay: staying up late, sleeping in.  Flying west.  Spring.  Using smart phones, tablets, and iPads in bed at night.  Light pollution.

Relative to adolescents, infants and children are circadian phase advanced.  This is part of what is fueling the movement to delay high school start times.  Kids are mentally better prepared to work later in the day.  With early school start times, performance is down in the morning, but they kill it on video games after school.  Delaying start time by an hour won’t totally fix this, but could help.

Edit: it seems like a similar movement is happening for adults, too – ie, starting work an hour later.

I’m not saying everything healthwise deteriorates with age, but the gradual circadian phase delay that occurs with aging and overusing blue light-emitting devices at night might not be a good thing.  If a particular diet can promote phase advance, why not? (at least it’d be countering the phase delay).



Possible role of diet

In the top half of the figure below, it’s mice fed a “normal diet (ND) (high carbohydrate)” (Oishi et al., 2012).  During normal “light dark (LD)” conditions, movement and feeding is concentrated in the active phase.  When the lights are permanently turned off in “dark dark (DD)” conditions, the free-running circadian clock begins to shift slightly forward (phase advance), but nothing drastic.


Phase advance high protein diet


In the bottom half of the figure, during normal LD conditions the mice are switched to a low carb, high protein diet.  Note how activity shifts leftward (phase advance) during the LD condition.  When low carb, high protein-fed mice are then switched to DD, we can see a clear circadian phase advance.


High protein metabolism


Low carb, high protein-fed mice ate more but didn’t get fat; physical activity and body temperature were unchanged.  But this post isn’t about that.  Gene expression of key circadian transcription factors in liver and kidney exhibited phase advances.

The next figure is study to the one above, although instead of switching to a low carb, high protein diet, the mice were switched to a low carb, high fat diet (Oishi et al., 2009).

Note the similarity of control (high carb diet) mice: gradual phase advance when switched to DD:


Ketogenic circadian phase


The phase advance is markedly enhanced in low carb, high fat-fed mice.

The circadian regulation of activity is similarly affected by low carb, high protein, and low carb, high fat diets.  What do those two diets have in common?

A bit of a stretch? carbohydrate restriction mimics some aspects of avoiding artificial light at night and being young: phase advance.  Whether the carbs are replaced with protein or fat doesn’t seem to matter in this aspect.


Wanna know what else can do this?  FOOD.  The food-entrainable oscillator (FEO) kickstarts circadian rhythms.  Rodent studies have shown that timed feeding, regardless of the actual time, consistently realigns the circadian expression of numerous genes (eg, Polidarova et al., 2011 and Sherman et al., 2012).

So what’s the hack?  Food: do more of it, earlier in the day.  Phase advance.  Kind of like avoiding artificial light at night or being young.


Oh, and mice exposed to dim light at night (who are pretty much metabolically screwed)? phase DELAYED (Fonken et al., 2010).


Dim light at night phase delay




calories proper


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  • Jack Kruse

    Nice job yet again, Bill. There is a reason the Leptin Rx uses the BAB. (big assed breakfast) The key point is to consider what might happen to your health when you advocate a “old type of diet” when your environment moves forward because of modern technology

    • Bill Lagakos

      Thanks, Jack. I’m all for a big breakfast (in the morning), if for nothing else, to avoid afternoon diabetes

  • Dan Ordoins

    Nice one Bill. Thanks.

  • Jane Plain (Woo)

    Another excellent blog entry, Bill.

    One point of contention. Although daylight savings time acutely causes a phase advance in fall and a phase delay in spring, the net effect on the human brain of these season changes is opposite. As light becomes progressively later (during the fall -> winter solstice) , total light exposure is decreased and the timing becomes later and later. The human brain is shifted toward a phase delay, sleeping and waking later. This is a depression trigger, and a major reason so many mood disorder pts struggle in fall.

    Spring is the inverse. The spring ahead is a phase delay, but the progressive earlier light all the way into the summer solstice and longer days are profoundly advancing. Many people get “spring cleaning” energy and bipolar patients may go manic from the circadian effect on neurotransmitters and alertness.

    Is minor point but an important one because the circadian system is very important to regulate for anyone with endogenous mood problem, and “fall” clusters with delay triggers for a reason (and depression). This will help other readers who have similar mood problems make sense of their symptoms and how to control them.

    If the keto diet is phase advancing this is powerful evidence to further support its role in mood disorders especially bipolar II with a preponderance of depression, or endogenous depression. Phase advancing is antidepressant.

    (FYI, lithium promotes a phase delay, which may also influence antimanic benefits)

  • Eric CFB

    Cold thermogenesis can also effect circadian issues.

    I’ve had serious sleep issues my whole life. Always used to miss school, morning college classes, dayshift jobs, cause I could never fall asleep at nite, or subsequently wake up the next morning.

    Cold thermogenesis has gone a long way to fix that. I’ve seen two ways this seems to happen.

    Doing CT at nite can help one get to sleep. First there is the catecholamine ‘dump’ one may experience, the rush and high of initial CT, followed by the ultra-mellow later on. And of course, CT lowers body temp, arguably mimicking the effects of melatonin:

    But then last year I started experimenting w/ morning CFB sessions (usually fasted or PSMF), and noticed that I would get sleepy that nite sooner, more tangible. It was as though the CT functioned to “wake me up” early, almost analogous to bright light therapy for nite shift workers.

    I’ve lost track of the amount of feedback reporting that the CFB/CT has helped them get a deeper sleep, but they’re all using it at nite, before bed. I’ve found that morning sessions can be just as effective, especially if you’re a “night owl” type.

    I suppose it causes “circadian phase advance.”

    • Bill Lagakos

      This is very interesting! Thanks, Eric.

  • Bill Lagakos

    “‘Social Jet Lag’ and the Teenager”

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  • Bill Lagakos

    School start times for adolescents.

    The American Academy of Pediatrics recognizes insufficient sleep in adolescents as an important public health issue that significantly affects the health and safety, as well as the academic success, of our nation’s middle and high school students. Although a number of factors, including biological changes in sleep associated with puberty, lifestyle choices, and academic demands, negatively affect middle and high school students’ ability to obtain sufficient sleep, the evidence strongly implicates earlier school start times (ie, before 8:30 am) as a key modifiable contributor to insufficient sleep, as well as circadian rhythm disruption, in this population. Furthermore, a substantial body of research has now demonstrated that delaying school start times is an effective countermeasure to chronic sleep loss and has a wide range of potential benefits to students with regard to physical and mental health, safety, and academic achievement. The American Academy of Pediatrics strongly supports the efforts of school districts to optimize sleep in students and urges high schools and middle schools to aim for start times that allow students the opportunity to achieve optimal levels of sleep (8.5-9.5 hours) and to improve physical (eg, reduced obesity risk) and mental (eg, lower rates of depression) health, safety (eg, drowsy driving crashes), academic performance, and quality of life.

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