What Time Of Day Can You Eat A “Cheat Meal,” How Cold Can Make You Unstoppable, Lies We’ve Been Led To Believe About Sunlight & Much More!

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This episode is all about light, but it's certainly not light on content!

See, the last time I was in Malibu, myself, music producer Rick Rubin and today's guest—Matt Maruca of RA Optics—spent plenty of time geeking out on all things light.

I've known Matt for two years now, and consider him to be one of the world's leading authorities on what is called “photobiomodulation,” or the use of specific wavelengths of light therapy to cause some very beneficial health effects. and also a guy who knows more about blue-light blocking glasses and limiting the harmful effects of artificial light than just about anyone I know.

Today's episode is a special two-parter. The first section is yours truly filling you in on how sunlight makes you skinny and blue light makes you fat. The second part is a special solosode from Matt, in which he fills you in on some of the little-known aspects of how to use light and how to block light in a way that will affect your energy, sleep, and mitochondrial health. You'll also learn the history of the use of sunlight for health, why the sun and skin cancer isn’t black and white, lots of research on how light affects human biology and the benefits of sunlight, how artificial light affects the body and much more.

Just to give you a “taste” of what you're about to hear: after preparing this episode, I asked Matt: “can you point me to a post or research on “best time of day to cheat if you are going to cheat” based on circadian rhythm/sun exposure? You alluded to it in the audio.”

He replied:

“I think it would be morning/mid-day. One of the factors leading me to say this is Ayurveda which I imagine you're familiar with. An Ayurvedic doctor I started working with explained this to me in their terms. Basically, in the middle of the day as the sun is stronger, the metabolism is more active. They call this energy “pitta”, or fire. So, we can burn through stuff pretty well. This is why they generally suggest eating “heavier” food in the middle of the day for lunch. And, it's a no brainer to me to fast through dinner because then the body can completely burn through everything you've consumed.

As for the Western Research, Satchin Panda from the Salk Institute leads the way. I recommend watching his TED talk where he explains their experiments on mice. They basically found that mice eating healthy food when their metabolism is turning off had way more problems than mice eating unhealthy food when their engines are running full force. Because they are nocturnal the times are reversed for them relative to us. So for us the best time would be late morning to mid-day.

To me, when eating this way I wouldn't even consider it a cheat because the body can move through stuff so well. If you are comparing to someone who is usually eating a “healthy” dinner at 7 or 8 PM, I am 100% convinced that it would be healthier to “cheat” every day in the middle of the day and fast through dinner then to do what that person is doing. Based on the research, there really is no such thing as “healthy food” after 5 PM or within 4 hours of sleep.

During our discussion, you'll also discover:

-The impact of light on human biology, for better or worse [8:10]

  • Deleterious effects of artificial light have been well researched
    • Recent studies show artificial light linked to breast cancer and sleep disorders
    • Exposure to artificial bright light at night suppresses melatonin secretion and increases sleep latency (how long it takes to fall asleep)
  • LEDs are replacing fluorescent bulbs (for better efficiency)
  • LEDs cause retinal damage, cell death in eye tissue
  • Dimming, color-changing features make things worse (flicker)
  • Flicker can cause irreversible damage to the retina
  • Oxidative stress damage
  • Photobiology: The study of the effects of ultraviolet, visible and infrared radiation on living organisms.
  • Book: The Influence of the Blue Ray of Sunlight
  • Red light used to treat smallpox in 1903
  • Phototherapy becomes therapeutic intervention
  • Book: Light Therapeutics by John Harvey Kellogg
  • Light affects metabolism
    • mTOR in the summer; AMPK in the winter
  • Being careful with light exposure allows you to strike a proper balance  between anabolism and catabolism

-10 light biohacking tactics to optimize your body and brain [17:30]

  • Use healthy light bulbs
    • Color rendering index (CRI)
    • Look for a CRI of 97 or higher in LED bulbs
    • Lower than 3000 color temperature (kelvin)
    • Avoid incandescents coated in white
  • Get as much morning sunlight as possible
    • Morning fasted walk in the sunshine
    • Eat a diet rich in fatty acids (Vitamin A and Vitamin D)
  • Block blue light as much as possible at night
  • Avoid artificial light (night and morning)
  • Use Iris Tech on all your monitors
  • Use anti-glare computer monitor
  • Use Light Dims while traveling
    • Bright light on the skin can affect the circadian rhythm
  • Install a Drift Box on your TV
  • Don't overuse sunglasses
  • Use photobiomodulation as much as possible

-How Matt Maruca became interested in light and blue-light blockers [41:55]

  • At age 14, didn't feel good in general; had acne issues
  • Changed diet to Paleo
  • Previous common health issues fixed themselves (thought they were genetic)
  • Influences: Ben Greenfield, Mark Sisson, Chris Kresser
  • Discovered epigenetics
  • Wandered from diet to diet with no real positive results to show for it
  • Discovered cold thermogenesis
  • Dr. Douglas Wallace linked dysfunctional mitochondria to chronic disease
  • Focused on the fuel rather than the engine as the cause of his illnesses
  • Explains why some people thrive on certain diets and others don't
  • Mitochondrial dysfunction is the problem; light is the solution

-The study of light exposure throughout history [58:00]

  • Several civilizations have studied the efficacy of light on human health
  • Egyptian Pharaoh was excluded from the annals of history because he believed in the power of light to enlighten his people
  • Hippocrates prescribed sunbathing often
  • Ancient Greek athletes used heliotherapy in their training
  • Christoph Hufeland, pioneer in macrobiotics, wrote of the deleterious effects of a lack of light on the body and spirit
  • 90% of kids had some sign of Rickets Disease during Industrial Revolution (lack of Vitamin D)
  • In 1903, Niels Finsen discovers UV light from sun kills TB of the skin (wins Nobel Prize for Medicine)
  • Auguste Rollier opens heliotherapy clinic in Swiss Alps in 1903
  • These discoveries create a “sun craze” – high in enthusiasm, low in knowledge
  • The modern indoor lifestyle causes our body to crave sunlight; however, the skin has not adapted for the level of sunlight we crave, hence the problems we see today

-The horrors of working and living under fluorescent lights [1:12:30]

  • 1980 study found the incidence of malignant melanoma is much higher among office workers; lowest risk was sunbathers
  • Can cause mutations in culture of animal cells
  • From 1957-80, no change in ozone levels in Norway; yet rate of malignant melanoma raised among men
  • Skin cancer rates have skyrocketed since 1900; yet most people work indoors
  • 2016 study showed that avoiding the sun is worse than smoking
  • You can develop a tolerance for sunlight with “solar callouses”
  • Know when your body is warning you

-How sunlight affects the body [1:19:00]

  • Benefits of ultraviolet light
    • Activates synthesis of Vitamin D
    • Lowers blood pressure (release of nitric oxide)
    • Increases efficiency of the heart
    • Improves EKG readings and reduces cholesterol
  • Avoidance of the sun is a form of malnutrition
  • You can never mimic ultraviolet light
  • Light is our life source; cells are designed to attract and capture light
  • Organisms emit UV light for up to 18 hours after dying (soul leaving the body after death)

-The importance of the circadian rhythm to our health [1:26:45]

  • Circadian rhythm
  • “Circadian” comes from two Latin words: circa (approximately) dias (one day)
  • Jesus spoke of the eyes as an indicator of our overall health, physical and spiritual
  • Eyes use a disproportionate amount of energy relative to its weight and size
  • Light coming into the eyes regulates the hypothalamus, which regulates the autonomic nervous system
  • 1953 study showed a circadian rhythm in every living creature
  • Blue light blocking glasses need to block only light that reaches the inner retina, not all light
  • The Circadian Code by Dr. Satchin Panda
  • BGF podcast w/ Dr. Panda
  • If we're ingesting even healthy substances when our engine needs to be shutting down, we're shooting ourselves in the foot
  • Melatonin optimizes our body, repairs mitochondrial DNA
  • Artificial light:
    • Created to extend work hours
    • Contain tremendous amounts of blue light
    • Harms our circadian rhythm

-Matt Maruca's Light Diet Protocol [1:49:50]

  • Sleep (and wake) with the sun
  • Rise with the sun and bathe in the morning light
    • Go to sleep early enough to rise with the sun
    • Set an alarm for 30 minutes before sunrise for 7 days
    • Avoid exposure to artificial light
    • Practice sun gazing
    • One hour walk outside can affect seasonal affective disorder (SAD)
    • Sunglasses are disruptive
    • Pink skin isn't a bad thing
  • Live outdoors during the day
  • Consume fatty seafood
    • Good for the eyes and the brain
  • Consume clean spring water
  • Bathe in cold water
  • Avoid man-made electromagnetic radiation
  • Cultivate your inner light
    • The light is who you are (your soul)

-And much more!

Click here for the full written transcript of this podcast episode.

Resources from this episode:

RA Optics (Matt Maruca's blue light blocking glasses company. Use code BEN10 for 10% off)

– Ben's new book at BoundlessBook.com – which has a whole chapter on light and other hidden environmental variables that affect your health

– Article: Sunlight Makes You Skinny & Blue Light Makes You Fat: 11 Ways To Biohack Light To Optimize Your Body & Brain.

– Book: The Influence of the Blue Ray of Sunlight by A. J. Pleasonton

– Book: Light Therapeutics by John Harvey Kellogg

Uvex blue light blocking glasses

True Dark glasses

Felix Gray glasses

Iris Tech

Light Dims

Eizo Flex Scan monitor

Drift Box

Vie Light


– Book: The Circadian Code by Dr. Satchin Panda

BGF podcast w/ Dr. Panda

Blue Light Has a Dark Side (Harvard Health)

BGF podcast w/ Jack Kruse

Blue free bulbs

Vintage Edison incandescent light bulbs

– Book: The Fourth Phase of Water by Gerald Pollack

BGF podcast on cold thermogenesis w/ Dr. Jack Kruse

Defender Pad

Cornet ED88T EMF/RF detector

Episode sponsors:

Ben's newest book: Pre-order Ben's new book Boundless or receive updates on its release via email

Kion Coffee: Carefully selected and roasted for taste, purity, high antioxidants and health. Ben Greenfield Fitness listeners, receive a 10% discount off your entire order when you use discount code: BGF10.

JOOVV: After using the Joovv for close to 2 years, it's the only light therapy device I'd ever recommend. Give it a try: you won't be disappointed. Order using my link and receive a nice bonus gift with your order!

Vuori: Activewear and athletic clothing for ultimate performance. Vuori is built to move and sweat in, yet designed with a West Coast aesthetic that transitions effortlessly into everyday life. Receive 25% off your first order when you use the link Vuoriclothing.com/Ben

Harry's RazorsTry the shaving company that’s fixing shaving. Get a $13 value trial set that comes with everything you need for a close, comfortable shave when you go to harrys.com/greenfield

Do you have questions, thoughts or feedback for Matt or me? Leave your comments below and one of us will reply!

Ask Ben a Podcast Question

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59 thoughts on “What Time Of Day Can You Eat A “Cheat Meal,” How Cold Can Make You Unstoppable, Lies We’ve Been Led To Believe About Sunlight & Much More!

  1. Bigg Nutrition says:

    Very good article shared, thanks for this.

  2. K Store says:

    Good information was shared, thanks for this.

  3. Carmen says:

    Hi Ben, Hi Matt,

    lately I’m having a hard time falling asleep and that’s why got interested in getting better & more sleep – and just being healthier overall. (also it might be influenced by my chronic illness(es)/autoimmunity).
    (already blocking blue light as best I can, meditate, using melatonin,…)
    I know the best thing would be getting morning sunlight and watch the sun rise. Nothing can replace the sun. As it’s winter in Germany the sunrise is at 7:30/8am… I will for sure try/do it on Sunday morning. I have to be at work from Mon-Fr, sometimes also Sat…. I just can’t get outside and see the sunrise (in the winter months). What’s the next best solution ? Light box in the morning that simulates sunlight? I have to be at work, so I can’t wear Re-Timer Glasses or those Ear Buds..
    Ben once recommended the NatureBright SunTouch Plus Light, but it’s not available in Germany (or no longer available at all).
    Thank you very much for your help!

  4. Thanks for sharing valuable information.

  5. Regis Moreau says:

    Another podcast talking about getting things that most people can’t afford.

    I’m slowly growing out of Ben’s podcast after 3 years.

    I stopped listening to D Aspray for that reason and i think Ben is next as i find him less & less relatable as his knowledge grows to use expensive bio hacks.

    I find his podcast less enjoyable as times goes on.

    His guests are the same, i never relate to any of them.

    Just my opinion.

    1. Jayce says:

      Glad I’m not the only one who gets annoyed with things that aren’t affordable. I still think there’s lot of good info, regardless. And some of this is doable. I find it’s a problem pretty much anywhere in the health community. Somehow these people all have tons of money and expect us to have tons of money to buy things.

  6. Todd says:

    @Ben – do you use the Edison bulbs from the link above, or something else? If something else, can you post a link to them?

  7. Scottieshobbies says:

    Another question.. As an auto tech in an LED lit shop, I’m looking for safety glasses (Z87+) with the technology to reduce the effects of flicker. Guessing a pair from amazon for $10.92 prob won’t protect against mitochondrial damage. Any suggestions would be greatly appreciated! Thanks again

  8. Adam says:

    When it comes to TV at night, I’m confused by the options. First, I wear contact lenses/glasses, so I assume RA Optics won’t work unless I keep contact lenses in longer than I usually do so I can see what I’m looking at. So Drift Tv is an alternative I guess (you wouldn’t need both RA Optics and Drift TV right?). But is setting your TV’s RGB setting to red also an alternative to Drift TV?

    1. Blue light blocking glasses can be worn with contact lenses. It really just depends on your preferences. Do you have other screens you're looking at (phone/tablet)? If so, I'd recommend the glasses. If it's just the TV and you don't want to wear glasses, drift box. And I'm not sure how much blue light is being blocked by altering your TV's settings. The cool thing about drift is that the transition is gradual, seamless, and almost entirely unnoticeable.

      1. Hi Ben: Do you have a discount code for Felix Gray glasses? Do you have any brands of blue blocking prescription glasses you recommend that I can get in the UK?

  9. Adam says:

    Does the sun gazing in the morning have to be done outdoors, or can it be done looking out the window? Also, the protocol to bathe in the morning sun would carry through the year, correct (even in the winter, when not much skin is exposed)?

    1. Matt Maruca says:

      Sungazing cannot be through glass, hence unfiltered. And yes, we need sunlight year round. Native Germans and Americans and everyone else wore loin cloths through winter. We have strayed far. Go outdoors like people used to 50 years ago, or like they did 10,000 years ago even better.

  10. Phil says:

    Hey Ben and Matt,

    thanks for the great podcast! I have a question: as I live in northern Europe where in winter it gets quite dark, especially in the morning, would it be a legit hack to buy a full spectrum daylight lamp and use it for 30 min in the morning as light therapy?

    Best regards,


    1. Matt Maruca says:

      No. The best hack would be to go outside in the morning when the light comes up, and avoid artificial light until then, or use blue blockers.

  11. Kevin Burch says:

    I have Iris installed with day settings of 2800K and 100%, on a MacBook retina display. Would you recommend I wear day blue-blockers while using it? Or is Iris taking care of things enough for daytime use? Thanks.

    1. Matt Maruca says:

      For daytime Iris is good enough but not at night.

  12. Sony says:

    Great content but the delivery was really dull, I prefer the interview style. Unfortunately this felt like he was reading from a book and for that reason it lacked the usual quality of enticing you to listen on to the end.
    It missed the interactive aspect.

  13. B says:

    In my opinion, it’s better having an interview with you and the guest having a conversation. New ideas are sparked when two people talk, that’s the magic.

  14. Justin says:

    Great content as always Ben thank you.

    I’ve been referencing the same study you did regarding the light behind the knee for a while…I recently listened to a podcast with Satchin Panda and Dave Asprey (who also had been using the same study as a common reference point for such things) and Panda said he had dug a little deeper into that study and the researchers had a tv on in the background in the room hence skewing any real results.

    I was just as surprised as Dave to hear this!

    Of course it doesn’t mean light on the skin at night is not having a detrimintal effect…I think it still ‘makes sense’ to sleep in a totally dark cave like environment…but I would like to see a well controlled study on it.

    1. Matt Maruca says:

      Forget about that study. That’s besides the point. Melanopsin is in the skin and fat in addition to the eyes. The skin is light sensitive. Period. https://www.nature.com/articles/s41598-017-16689-4 . More research = great but the point is there.

  15. Karina says:

    What about point nr. 9 If you are leaving in Iceland you need to go for vacation to California twice a year ;)

    Guys it was so nice to hear all of this I’m so proud that I do all of the hacks ;) and bio hacks ;)

    It was grate to hear science behind this so I can explain better, when someone ask me why I do all this weird stuff hehe!

  16. Keith says:

    Hey Ben/Matt,

    Question about photobiomodulation. I have a Joovv, can i use mirrors to reflect the light to cover the whole body at the same time. will it have the same effect?

    1. Matt Maruca says:

      The mirror will reflect the visible red light although the intensity will be reduced. I am not sure that it will reflect the near IR as it will likely be absorbed by the glass material.

  17. scottieshobbies says:

    Hey Ben and Matt,

    We have a new mattress on the way from BioPosture.com. Wondering if you could look into the “Celliant” technology used that absorbs body heat energy and reflects it back as infrared light. Research shows this HELPS sleep. Greatly appreciate your thoughts. Thanks!

    1. This would be a good question to call into the podcast. https://speakpipe.com/bengreenfield

      1. Scottie says:

        Tried it but wouldn’t play it back. Not sure if it went through.

  18. Vlad says:

    This new format is dull and unlistenable. Monologues are hard to listen and pay attention to. Bring back the dialogue.

  19. Ann says:

    Is this a junior high school science report? If so, I would give it a B. But this isn’t supposed to be for an educated adult audience right?

    1. Matt Maruca says:

      Hey Ann! We do our best to bring you valuable information. It’s OK if you think the work is light a junior high school science report. You don’t have to listen :)

      To those reading this– it is possible that Ann lacks adequate morning UV light exposure. This leads to inadequate dopamine production, which leads people to be irritable, but especially to have lowered trend recognition; having trouble seeing the forest through the trees.

  20. Gregory Mendizabal says:

    Hi Matt & Ben

    Great podcast!!

    I was wondering about the thought and recommendation on contacts not letting UV through and just wear glasses in the morning. What are your thoughts on contacts that do not block or have UV protection?


    1. Matt Maruca says:

      All contacts reduce UV light. They also reduce oxygen to the eye. This is really bad.

  21. Will says:

    Hi Ben,

    I love this episode. I have been wanting to learn more about light therapy. Just a quick question. If I can only afford to by one Joovv Go device, should I get the Red light or the NIR version if it’s for the purpose of testosterone enhancement (i.e. shining on my gonads)?

    1. Matt Maruca says:

      Neither will have an effect even close to that of morning sunlight, if your goal is testosterone enhancement.

  22. Olafur says:

    Great pod but a bit depressing for someone living in Iceland. We only have 4-6 hours of daylight (sunny days rare) from Nov-Feb. Any tips on how to cope with that? I find my fatigue and pain levels go way up over those months.

    1. Matt Maruca says:

      Lots of sauna, seafood, time outdoors when it is light, cold exposure, hot pool bathing, and especially lots of sunlight during the summer to store Vit. D in your fat.

  23. Richard says:

    Great episode. Ben, can you be specific on your Eizo monitor? They have lots of models on Amazon including LED and LCD.

    Also, have you ever looked into tan-through shirts and swimwear? Legit?


    1. Matt Maruca says:

      Better to get direct sunlight. They reduce the light tremendously.

  24. Virgil says:

    Is this the article on deep sleep you told us about a few podcasts ago, Ben, or that one is coming later?

  25. Anthony C Petitt says:

    Ben, this guy Matt Maruca, at 20 years old moreover, is a Prodigy! I absolutely loved this podcast. He needs his own podcast!

    1. Matt Maruca says:

      Thanks Anthony! I appreciate it. I’ll get there. I’m focused on my business at the present moment.

  26. Rob Kay says:

    One thing to add to this awesome podcast. When you interviewed the guy who wrote iris a few years back he made a throwaway comment that e-ink screens do not flicker and emit no blue light and therefore cause you no issues. I got to thinking what if I could use e-ink for a regular computer screen? You can…

    Several manufacturers now make android e-ink tablets. By simply using a free vnc app to remote control any computer (with mouse and keyboard if you want…) you can use your computer outside in sunlight with no artifical light/lcd screens etc. You can even just about watch videos in black and white. The difference between using an iris running pc for a few hrs a day vs using an e-ink tablet is literally night and day. I actually use two so I have to look back and forth between them as I work.

    I hope this helps someone as much as it has helped me. I’ve spent my entire adult life battling health problems – the root of which appears to be light related issues. The information I got from this podcast over the last few years has been massively important in understanding how to change my environment to give my eyes a chance to recover and finally the cold showers, intermittent fasting, weston price but lite on the animal produce diet are actually making a difference rather than banging against a brick wall… the last few years my health has improved leaps and bounds thanks to you. thankyou…

    1. Matt Maruca says:

      That is awesome! Yes, e-ink screens will not have flicker unless the lighting used to light the e-ink at night when it’s dark has flicker.

  27. nemiah louis says:

    I thought Matt was incredible, I listented to the entire podcast on a long road trip and my brain was throbbing (in a good way) . I’ve finally made the journey to get into the light side of biohacking. Ben you have found your next co host.

  28. Stephen Jelley says:

    Sorry but the format does not work do me.

  29. steve szakal says:

    I got the impression that Matt was just making up shit, and once people start talking about “the ancients” I zone out….they used to do things like bleed people out and other really weird shit…they were pretty dumb….

    1. Kelly Penny says:

      Actually there are health benefits to blood letting. Check out benefits of routinely giving blood, esp for men.

    2. Matt Maruca says:

      Hey Steve! If you know how to use Google or Google Scholar, you can go in and check out any of the mentioned research and names yourself, and draw your own conclusions. I don’t know everything; far from it. Just trying to share what has helped me. Best of luck to you, sir!

  30. Carlos says:

    Hey what are your thoughts on Himalayan salt lamps?

  31. GJ says:

    Hello Ben / Matt.

    Epic episode. Loved it! Now i have a question about blue blockers.

    Since few weeks i have blue blockers. “Problem” is, it is way to big for my head. (As in, there is a lot of space between my head and the glasses).

    – Is it a problem that the model is to big?

    I heard jack kruse saying light travels not in a straight line, non-linear. Can blue light from a device reach my eye more easy when wearing an over size model? Hope to hear your take on this!


    Best regards . GJ

    1. Matt Maruca says:

      Hi GJ!

      As long as your eye is covered, you are good.

      Try one of our styles from raoptics.com. They fit very well for most faces. Use code BEN10 for 10% off.

  32. Jane says:

    Hi Ben

    I remember in a previous article you use the JOOVV for 10mins every day, is that still the case?

    I’ve read that overuse activates the ‘bi-phasic response’ , but don’t know much about it other than your cells no longer respond to the LLLT, is that correct?



  33. Michael says:

    Hi Ben,

    You listed some of your favorite blue light blocking glasses and Swanwicks were not one of them. I have a pair and I am wondering if they are not sufficient or are one of the cheap pairs you referred to. Thanks!


    1. Swanwick has some great glasses.

    2. Matt Maruca says:

      Michael, if you have a newer model, they are OK. Ours block a greater spectrum and therefore the effects are better for sleep. Theirs only block up to 500nm whereas ours block up to 550nm, giving them their darker red/orange color (see our instagram @ra_optics for real life photos of how they appear. Also, our frames are more attractive and higher quality across the board.

  34. Leigh says:

    Hey Ben, love your podcasts, by some distance my preferred health and fitness related one. In this episode you mention not overdoing the photobiomodulation which I’ve seen previously, however it seemed like you included the full spectrum sauna in that grouping…..I always thought that they were different MOA and would be complimentary (i.e. 15 mins photobiomodulation and 20 mins sauna a day) but wanted to double check as I’m about to get both…..??

    1. Matt Maruca says:

      Yes, both would be great. None will make up for a deficiency in sunlight, however.

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