Seth Roberts and Circadian Therapy

A while back I noted that hypothyroidism is a circadian rhythm disorder and that dietary steps that restore circadian rhythms, like intermittent fasting and daytime eating, should be therapeutic (“Intermittent Fasting as a Therapy for Hypothyroidism,” Dec 1, 2010).

Many other disorders besides hypothyroidism feature disturbed circadian rhythms:

  • Sleeplessness and poor sleep
  • Depression, bipolar disorder, and other psychiatric disorders
  • Dyslipidemia, metabolic syndrome and obesity.
  • Neurodegenerative disorders

Circadian rhythm disruption also suppresses immune function and increases vulnerability to infectious disease.

Restoring or strengthening circadian rhythm may be therapeutic for all of these conditions. Even for healthy people, tactics for enhancing circadian rhythms may improve health.

Which brings us to Seth Roberts.

Seth Cured a Sleep Disorder With Circadian Therapy

Seth is a well-known blogger, a Paleo dieter and psychologist, author of  The Shangri-La Diet, and a great self-experimenter.

Seth recently gave a talk that tells the history of his self-experimentation.

It turns out he suffered from disturbed sleep for many years. He experimented to find cures for 10 years; nothing worked. But then he got a lead.

When a student suggested he eat more fruit, he started eating fruit for breakfast. His sleep got worse! This was exciting to Seth because it was, in 10 years, the first thing he tried that changed his sleep.

He had the idea of trying no breakfast. It turned out that skipping breakfast improved his sleep. One of his slides:

This directly supports our idea that intermittent fasting (confining eating to an 8-hour window each day) should be therapeutic for circadian rhythm disorders such as disturbed sleep and hypothyroidism.

But what’s exciting is that Seth continued his experiments to find other ways to improve his sleep. As a psychologist, he knew that human contact controls when we sleep: people are most awake at the times they have contact with other people, and asleep when isolated.

He knew that watching TV can have effects similar to socializing. So he tried watching Jay Leno one morning. He slept very well the next night.

It turns out that looking at human faces is almost as good as real socializing. Here is Seth’s data relating mood to whether he looked at faces:

Seth also tracked his mood over the course of the day. The response of mood to seeing pictures of human faces clearly followed a circadian (24-hour) rhythm:

Another thing that relates to circadian rhythms is exercise: we normally exercise during the day and rest at night.

For a scholar, the easiest way to exercise is to stand rather than sit (for instance, by working at a standing desk). Seth tried standing 9 hours a day – and it cleared his sleep problem!

Of course, standing is not a very strenuous exercise. Seth found that if he just stood on one leg, the effect was much more intense, and he could fix his sleep problem with only minutes of one-legged standing per day.

He also found that eating more animal food improved his sleep. It’s possible that animal fat may enhance circadian rhythms more than other foods.


I found this fascinating – because it adds more evidence regarding the centrality of circadian rhythms in health – and exciting, because it shows that simple tactics can be therapeutic for circadian rhythm disorders.

In the hypothyroidism post, I suggested the following tactics for improving circadian rhythms:

  • Light entrainment: Get daytime sun exposure, and sleep in a totally darkened room.
  • Daytime feeding: Eat during daylight hours, so that food rhythms and light rhythms are in synch.
  • Intermittent fasting: Concentrate food intake during an 8-hour window during daylight hours, preferably the afternoon. A 16-hour fast leading to lower blood sugar and insulin levels, and the more intense hormonal response to food that results from concentration of daily calories into a short 8-hour time window, will accentuate the diurnal rhythm.
  • Adequate carb intake: Eat at least 400 “safe starch” carbohydrate calories daily during the afternoon feeding window. Relative to a very low-carb diet, this will increase daytime insulin release and, by increasing insulin sensitivity, may reduce fasting insulin levels. It will thus enhance diurnal insulin rhythm.

To these, we can add several more based on Seth’s findings:

  • Looking at human faces: If you work at a computer, keep a window up that cycles among photos of faces, or shows a video of a talk show; keep photos of your family near your screen.
  • Standing: Work at a standing desk or, failing that, get in the habit of standing on one leg rather than two.
  • Animal fat: Eat a diet high in animal fats.

These tactics cured Seth’s sleep disorder. Might these tactics also cure or greatly improve other circadian rhythm disorders – including hypothyroidism and psychiatric disorders like depression and bipolar disorder? Could looking at human faces help the obese lose weight and improve their lipid profiles?

I don’t know but I’d certainly give these techniques a try before pharmaceutical drugs. I believe these techniques deserve clinical testing as therapies for all diseases associated with disrupted circadian rhythms. I believe that they may be just as beneficial for the healthy: by improving immune function, they may delay aging and extend lifespan.

A few weeks ago, when I posted a video of Don Rumsfeld defending the use of a standing desk (the same video was later linked by John Durant and Mark Sisson), I brashly stated, “There are few single life adjustments more likely to improve your health than working at a standing desk.”

Perhaps that statement wasn’t as exaggerated as it may have seemed!

Seth’s Talk

Leave a comment ?


  1. Hi Paul,

    I wonder what you acutally consider as a good circadian rhythm? Getting up exactly when the sun rises and fall asleep at sunset?

    For three years I cannot fall asleep until 3-5am but then I have no problem to sleep for full 7 hours straight. Definitely out of synch though I get my dose of sleep but also seeing no progress for a endless list of health conditions.
    Even as a child I was so tired in the mornings that I would have to take a nap in the afternoon after school every day.

    Just bought the book and I will start to follow all recommendations soon. Thanks.

    • Hi Chris,

      I would say the keys are:
      - Getting at least 2 hours per day of sunlight or very bright blue light distributed over a 10-12 hour period. Maintain lights as bright as possible over the rest of the period.
      - Getting 10-12 hours of essentially no blue light exposure; ie use amber light bulbs and f.lux on the computer, or wear blue-blocking amber goggles.
      - Eating meals within or close to the period of bright light exposure.
      - Sleeping at a consistent time and to a natural waking during the period of darkness.
      - Physical activity within the bright day period — preferably 30-40 minutes every day.
      - Social interaction and engagement during the day.

      Best, Paul

      • With the 2 hours of sunlight, do you mean out in sunshine? Do clouds or shade negate the positive effects of being outdoors?

  2. Regarding “viewing human faces” in the evening as being disrupting to sleep … how would you apply this to children’s shows? If I allow my children to watch cartoons in the evening, will that stimulate them? Do cartoon faces count as human faces? My kids don’t watch a lot of tv, but we do sometimes watch a show after dinner just to get them to sit down. :)

    • Hi Robyn,

      I think it probably does stimulate them, but I think it’s infeasible to avoid it. We often watch movies after dinner; it is not optimal for circadian rhythms I think, but it is optimal for our happiness.

  3. I would love to hear your response to this article which suggests that eating the majority of your calories first thing in the morning is better for weight loss and health. It seems to contradict the intermitent fasting theroy.


    • Hi Brooke,

      It wasn’t testing intermittent fasting — it was comparing similar eating schedules with relatively more calories early than late, or late than early. Intermittent fasting is well supported. The comparable idea would be, should your feeding window be early in the day (ie 8 am to 4 pm) or late in the day (noon to 8 pm). This might support an early feeding window. But that is an extrapolation that is really hard to trust. I think an early feeding window would work well. The one thing we know for sure is that feeding should coincide with daylight, if possible.

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  8. Is it normal after a 16h fast to have a BS reading of 97? I had dinner last night around 8.15. Today i woke up at noon and measured my BS. I was very surprised when it read 97. I dont have diabetes. I used to have episodes of reactive hypoglycemia but its totally gone after 3 months on the PHD. Should i be concened by this number? Isnt it too high following a 16h fast? Please help. Thank you

  9. Hi Paul,

    Do you believe tryptophan-rich foods could help? If so, would evening be preferable?

    Seth wrote that eating animal fat, particularly bacon fat, improved his sleep. I know bacon has a high amount of tryptophan (not too sure about bacon fat, or butter or tallow, for that matter).

    Any thoughts?



  10. Any advice for someone who works the nightshift?

    I get up at 11PM and go to sleep at around 4PM.

  11. Hello Paul,
    I’m actually the opposite in that when I’m eating unhealthy and over weight I sleep great. When I start to eat healthy, currently on PHD, my sleep suffers. It’s not PHD because the same happened with Paleo or any other plans I’ve been on.
    No stress, following all principles: magnesium, darkness, schedule: intermittent fasting (eating 12-8) in bed by 10, waking at sunrise.
    Within 2 days of getting back on the “healthy” programs like clockwork I wake up 2:00 am and have trouble getting back. When I’m fat, 9/10 solid hours easy??
    I would like to stay on my new healthy regimen, but I miss my sleep.

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