Many people consider light to be, well, light!
After all, light is just a wave of energy that signifies the absence of darkness, right? Fact is, light has a profound impact on human biology, for better or worse. In my last article on sleep, you learned plenty about the effects of artificial light and blue light on circadian rhythm and sleep, and in other articles, I’ve filled you in on biohacks such as photobiomodulation, near infrared, far infrared, UVA and UVB, including: How Modern Lighting Can Destroy Your Sleep, Your Eyes & Your Health, The Ultimate Guide To Biohacking Your Testosterone, How To Use Low Level Light Therapy and Intranasal Light Therapy For Athletic Performance, Cognitive Enhancement & More. & What’s The Healthiest Way To Tan
But the effects of light go far beyond its potential for positively hacking sleep or enhancing recovery, especially when it comes to the potential for artificial light to damage your overall wellness. The negative health impact of artificial light sources on endocrine and cellular levels in humans includes the risk of cataracts, blindness, age-related macular degeneration, mitochondrial dysfunction, metabolic disorders, disrupted circadian biology and sleep, cancer, heart disease and more.
For example, multiple recent studies have reported that exposure to artificial light can cause negative health effects, such as breast cancer, circadian phase disruption and sleep disorders. One 2015 study reviewed 85 scientific articles and showed that outdoor artificial lights (e.g. street lamps, outdoor porch lights, etc.) are a risk factor for breast cancer and that indoor artificial light intensity elevated this risk. This same study also showed that exposure to artificial bright light during nighttime suppresses melatonin secretion and increases sleep onset latency and increases alertness and that the circadian misalignment caused by artificial light exposure can have significant negative effects on psychological, cardiovascular and metabolic functions.
One perfect example of the effects of modern light on human biology is that of LED (light-emitting diode), which is rapidly replacing compact fluorescent (CFL) bulb, primarily because LEDs do not contain mercury like CFLs and they’re far more energy efficient. LED lighting is used in aviation lighting, automotive headlamps, emergency vehicle lighting, advertising, traffic signals, camera flashes, and general lighting. Large-area LED displays are also used in stadiums, dynamic decorative displays, and dynamic message signs on freeways. But LED’s pose significant environmental risks and toxicity hazards due to their high amount of arsenic, copper, nickel, lead, iron, and silver.
But LED’s can also cause severe retinal damage to the photoreceptors in your eye and have even been shown to induce necrosis (cell death!) in eye tissue. The American Medical Association even put out an official statement warning of the health and safety issues associated with white LED street lamps. Things get even worse once dimming and color changing features are introduced into LED lighting, which is a common lighting feature in modern “smart homes”.
The reason for this is that LED lamps are a form of digital lighting (in contrast, the incandescent light bulbs and halogens light bulbs you’ll learn about momentarily are analog thermal light sources). In a color changing system that allows you to adjust the dim or color of the lights, there are typically three different LED sources: red, green and blue. The intensity of these three sources has to be changed to achieve different colors, and this feature must be controlled digitally via a mechanism called pulse-width modulation. This means the LEDs rapidly alternate between switching to full intensity and then switching off over and over again, resulting in a lighting phenomenon called “flicker”, something I recently discovered during my Building Biology analysis occurs quite a bit even in my own biologically friendly home (influencing me to make some of the lighting changes you’ll read about later in this article) and something that I’ve also learned quite a bit about from my friend Dr. Joe Mercola.
Even though it appears to your naked eye that the LEDs really aren’t changing color or intensity that much, your retina perceives this flicker, and you can often observe this phenomenon if you use an older camera, or a device called a “flicker detector” to record an LED light in your house or an LED backlit computer monitor. Unfortunately, this trick doesn’t work with newer cameras and smartphones, which have a built-in algorithm that detect the flicker frequency and automatically change the shutter speed to improve the recording quality. However, I’ve found that by switching my iPhone to slow-motion video recording, I can often detect flicker in a monitor or light. Ultimately, the problem is this: research has shown that this flicker can irreparably damage the photoreceptor cells in the eye’s retina, resulting in issues such as headaches, poor eyesight, brain fog, lack of focus, increased risk of cataracts and sleep disruptions.
Unfortunately, energy saving lamps such as compact fluorescent lamps (CFLs) can also cause similar issues and can induce oxidative stress damage that affects not only the eyes but also sensitive photoreceptors on many other areas of the skin, along with endocrine and hormonal damage.
But light can be good too and in fact, the therapeutic use of full spectrum light – also known as “photobiology” – offers many surprising health benefits. For example, in the 1700’s, scientist-inventor Andreas Gärtner, built the first phototherapeutical device, which was a foldable hollow mirror he could use to concentrate sunlight onto the aching joints of patients. A gold leaf on the mirror absorbed UV radiation from sunlight, then transformed this light into near-infrared and red wavelengths very similar to those used in modern times by people who use infrared saunas to manage joint pain. , which is beneficial because it can penetrate deeply into the tissue. In the 1800’s, a General Augustus Pleasonton published the book “Influence of the Blue Ray of the Sunlight“, in which he describes “Influence Of The Blue Ray of Sunlight and Blue Colour Of The Sky In Developing Animal And Vegetable Life And In Restoring Health From Acute And Chronic Disorders To Humans And Domestic Animals”. In the late 1870’s, Dr. Edwin Dwight Babbitt published his book, “Principles of Light and Color“, reporting on research in which he used colored light on different parts of the human body to elicit therapeutic results. In 1897, Indian physician Dinshah Ghadiali used chromotherapy in the form of indigo-colored light as a treatment for gastric inflammation and colitis, and late 19th century Niels Ryberg Finsen of Denmark, who was awarded the Nobel Prize for Physiology in 1903, used red light to treat smallpox, and other light spectrums to address chronic disease such as tuberculosis. In the decades following, Finsen phototherapy became more developed as a cutting-edge therapeutic intervention in modern medicine, including the groundbreaking book “Light Therapeutics” by Dr. John Harvey Kellogg and work by Dr. Oscar Bernhard, a Swiss surgeon who used heliotherapy (sun therapy) during surgeries.
Light can drastically affect our metabolism too. For example, the master fuel sensor in our cells called mTOR (“mammalian target of rapamycin”) facilitates protein synthesis and growth while inhibiting internal recycling of used or damaged cells. Plants and humans grow more in the summertime because there is not only more food abundance but usually more natural light too, which can activate mTOR. But your body needs a darkness – a winter, so to speak. The master fuel sensor in the winter, and in darkness, is AMP-0activated protein kinase (AMPK) which optimizes energy efficiency and stimulates recycling of cellular materials. This cycle happens during the night. Now, consider what happens if you are in a constant stage of light: your hormones and metabolism shift towards constant mTOR activation growth and anabolism – which is generally associated, when in excess, with issues such as cancer and shortened lifespan. On the flipside, by introducing periods of darkness (along with, ideally, fasting), you strike a balance between constant anabolism with zero cellular cleanup and smart catabolism with adequate time for natural cell turnover.
So how can you mitigate the damage of the wrong kind of light and maximize the benefits of the right kind of light? You’re about to find out, along with how sunlight makes you skinny, blue light makes you fat and 11 ways to optimize light in your home and office environment.
11 Ways To Biohack Light To Optimize Your Body & Brain.
#1: Choose Your Lighting Carefully.
One way to ensure you are purchasing a healthier lightbulb is to look at at a value on the light label or box called the Color Rendering Index (CRI). CRI is a quantitative measure of the ability of a light source to reveal the colors of various objects accurately in comparison with an ideal or natural light source. For example, sunlight, incandescent light bulbs and candles all have a CRI of 100. When purchasing LED, look for an R9 (full red spectrum) CRI of close to 97, which is the highest CRI you are likely going to be able to find and can get you as close as possible to natural light. You also need to look at the color temperature of the light, which is the temperature of the light expressed in Kelvin (K) degrees. For example, the sun has a physical color temperature of 5,500 K, and a correlated color temperature (how the light source appears to the human eye, of about 2,700K. So although many LED’s have a color temperature of up to 6,500K, an ideal LED choice would be an LED with a color temperature as close as possible to 2,700K (in comparison, most incandescent lamps have a maximum color temperature of 3,000 K, since the light filament would melt if the temperature were any higher).
You can also consider the use of “biological LED”. For example, the company “Lighting Science” produces a line of biological bulbs that give off light meant to complement the circadian rhythm, not disrupt it. The light that emanates from Lighting Science’s Sleepy Baby bulb, for example, does not interfere with melatonin production, the hormone that helps you and your baby sleep, and is designed to be as close to candlelight as possible. In contrast, their GoodDay spectrum of light is engineered to provide light energy largely missing from conventional LED, fluorescent and incandescent sources, specifically providing a rich white illumination with high color rendering inspired by morning sunlight that supports alertness, mood and performance. Unfortunately, while these light bulbs are a decent option for “customizing” certain areas of your home to have high or low amounts of blue light depending on whether that area of the home is a “waking” area (e.g. office, gym, garage) vs. a “sleeping” area (e.g. bedroom, master bathroom, etc.), they still do produce a significant amount of flicker based on both my own testing and the testing of the building biologist I hired to audit my home.
For the ultimate solution, although it can be more expensive and far less energy efficient, I recommend switching as many lightbulbs in your home and office as possible to A) the old-school style of clear incandescent bulbs, preferably without any coating (which changes the beneficial wavelengths) B) a candlelight-style organic light emitting diode (OLED), which is a human-friendly type of lighting because it is blue-hazard-free and has a low correlated color temperature (CCT) illumination, which means the candlelight style is deprived of high-energy blue radiation, and it can be used for a much longer duration than normal LED’s without causing retinal damage.
If you decide to go with incandescent, many incandescents are not clear, but instead coated with white to make them more aesthetically pleasing. Steer clear of these, and instead choose a 2,700 K incandescent light bulb or a low-voltage halogen lamp. The one benefit of the latter is that low-voltage halogen lights are very energy efficient compared to a standard incandescent lamp. However, most halogens operate on an alternating current (AC), which generates a large amount of dirty electricity, so you must use a direct current (DC) transformer with them. The problem is that to do this, you need an inverter switching power supply to convert AC to DC, and this can cause high voltage transients (dirty electricity) and relatively high electrical fields, both of which were measured by my friend Dr. Mercola when he tried to pull this off. So the only way to make a halogen lighting solution work is to go off-grid and switch your entire house to all DC power, or to use solar panels with no AC inverter installed, and used the solar power battery to run the halogens. I suspect this is too much trouble for most folks, and because of that, a limited use of biological LED along with either low-temperature incandescent bulbs or blue-hazard-free candlelight OLED lighting appears to be the best option.
#2: Get Morning Sun
Unless you’re trying to send your body a message that it “isn’t morning yet” to shift your circadian rhythm forward (see my last big article on sleep), you should actually expose yourself to as much natural sunlight as possible first thing in the morning. In fact, the more sun you get in the morning, the more melatonin you make at night. A morning, fasted walk in the sunshine is one of the best ways to optimize your overall health, and the full spectrum of UVA, UVB and near and far infrared from sunlight can also mitigate some of the damage of artificial light the rest of the day.
Interestingly, based on research by my friend Dr. Chris Masterjohn, it turns out that if you are deficient in the fat-soluble vitamins A and D, your photoreceptors become less sensitive and the strategy of getting adequate sunlight becomes less effective – so be sure to implement everything that makes sunlight able to charge your internal battery, including not only a diet rich in healthy fats, but also high in minerals, clean, pure water and frequent skin contact with the planet Earth. This is also yet another reason I am a fan of daily use the SuperEssentials brand of fish oil: not only does it have high amounts of Vitamin A and D added to it from purified fish liver oil, but it also contains a full milligram of astaxanthin, which can protect photoreceptors from oxidative damage generated by artificial light!
#3: Use Blue Light Blockers.
Seven years ago, in an attempt to minimize the slight headache and eye discomfort I often experienced after spending long periods of daytime work on my computer, I purchased my first pair of “biohacked” glasses from a company called Gunnar. While these glasses significantly reduced my exposure to monitor flicker and even allowed me to wander through malls and grocery stores without being bothered as much by the harsh artificial lighting, blue light blocking technology has come a long way since then. For example, many companies, such as Amber (code: GREENFIELD), Felix and Swannies (code: GREEN10), now produce untinted, anti-glare glasses that can block the higher range of the blue light spectrum, and other brands, such as Spektrum, produce slightly tinted glasses that reduce even more of the blue light spectrum. Gunnar and Swannies now make yellow-tinted glasses that block most blue light, and Ra (code: BEN 10), Uvex and True Dark make orange and red-tinted glasses that block all blue light. I personally wear clear or yellow lenses for daytime computer work, nighttime dinners out or driving at night, then switch to the more effective but far less attractive orange or red lenses for the evening at home. If you want to get very specific with blocking the most harmful wavelengths of light, you should check that the glasses block the spectrum of 400-485nm (The Ra glasses are an example of a lens that blocks that specific spectrum).
#4: Avoid Artificial Light Not Only At Night, But In The Morning Too.
You’ll often hear that you should be careful with isolated and concentrated sources of blue light at night, but this rule applies to the morning too. Especially until you’ve gotten out into the sunlight, you should avoid artificial light as much as possible in the morning, particularly by limiting harsh, concentrated sources of blue light such as artificial home and office lighting or bright screens, and by instead opening curtains to allow as much natural light into the home and office as possible. In addition, you’ll often find me wearing blue light blocking glasses for the first couple hours of the morning, and avoid turning on the kitchen lights, bedroom lights, etc. unless absolutely necessary (trust me: making a big cup of hot coffee in the dark isn’t a good idea).
#5: Use Red Light In The Evening.
For the bedroom, consider red incandescent bulbs, particularly in the light fixtures near the bed. Candles are also an excellent option for both the bedroom and the dinner table, although you must choose fragrance-free, natural palm or beeswax candles, since many modern candles are riddled with paraffin, soy, toxic dyes and fragrances. If your phone or e-reader has the option, always switch it to night mode or, better yet, red light mode in the evening. Here’s exactly how to do”The Hidden Smartphone Red Screen Trick”.
#6: Install IrisTech On All Monitors.
I first became aware of IrisTech software when I interviewed a 20-year-old, brilliant Bulgarian computer programmer named Daniel Georgiev on my podcast. Daniel invented a special piece of software that goes far beyond the blue-light blocking computer software called “F.lux” that many people are already familiar with. IrisTech controls the brightness of the monitor with the help of your computer’s video card, allows you to have adequate brightness without monitor flicker, reduces the color temperature of your monitor, optimizes screen pulsations to reduce eye strain, adjusts the brightness of your screen to the light around you, and even automatically adjusts your computer monitor’s settings based on the sun’s position wherever you happen to be in the world. It has settings for pre-sleep, reading, programming, movies and many others, and even allows you to receive pop-up reminders for activities such as eye exercises and stretching. Click here to get IrisTech.
#7: Use An Anti-Glare Computer Monitor.
Fancy, modern LCD monitors are not flicker-free, even though many people think they are because they don’t seem to appear as harsh as older computer monitors. These LCD monitors originally started out by using something called CCFL (cold cathode fluorescent lamps) as a backlight source for the monitor, but in recent years manufacturers have shifted to using LEDs (light emitting diodes). If you have one of those thin monitors, then you probably have an LCD monitor with LED, and if you are unsure, you can check the model number on the backside of the monitor and Google it. Due to the way brightness is controlled on LED backlights, it produces the same LED light flicker you’ve already learned about. The monitor I use is an Eizo FlexScan EV series, which regulates brightness and makes flicker unperceivable, without any drawbacks such as compromised color stability. It allows you to lower the typical factory preset color temperature setting of 6,500 K down to the more natural 2,700K and also has a “Paper Mode” feature, which produces long reddish wavelengths and reduces the amount of blue light from the monitor. The Eizo monitors also have a non-glare screen, which reduces eye fatigue by dissipating reflective light that otherwise makes the screen difficult to view.
#8: Use Light-blocking Tape Or Stickers.
Even if you are blocking light from reaching your eyes at night by using blue light blocking glasses, a sleep mask, black-out curtains, etc., you still need to be cognizant of items in your bedroom that produce LED lights, such as televisions, clocks, power strips or computer chargers. This is because even if your eyes are covered, your skin has photoreceptors that can detect all these sources of light. Even if you have mitigated all light sources in your own bedroom, walking into any hotel room at night presents you with a veritable Christmas tree-like lighting experience. at hotels. Fortunately, you can easily purchase simple and affordable light blocking pieces of tape, such as “LightDims” that are specially designed, removable tiny covers which act like sunglasses for irritating LEDs on electronics. They can dim or completely cover unwanted LED glare or flare in any room. You simply peel off a sticker and apply it to your electronics, keeping them functional while dimming annoying LEDs to a comfortable or completely unnoticeable level. If you ever feel like you are being bombarded with LED’s or external sources of light in any room – even when you feel like you’ve already shut everything off, these stickers work perfectly.
OK, I’m going to stop for a second and go down a rabbit hole here: why on earth would you want to limit the amount of light that your skin is exposed to? Frankly, because your skin is an eye.
See, in the animal kingdom, light-sensing photoreceptors that go far beyond the eyes are actually quite prevalent. Most of the photoreceptors scientists have found outside the eyes are usually located in the brain or the nerves (or in insects, on the antennae).
But a number of different photoreceptors have been found on animal skin too, particularly in active color-changing cells or skin organs called chromatophores. You likely know these better as the black, brown or brightly colored spots on fish, crabs, frogs, octopus and squid. In many cases, animals can control these chromatophores for camouflage (to match the color and pattern of a background) or to produce colorful signals for either aggression or attracting a mate.
But aside those photoreceptors utilized for camouflage or mate attraction, what in the world is the purpose of all the other photoreceptors? It appears that they help to maintain a normal circadian rhythm, even without precise knowledge of a light source’s location in space or time. These circadian rhythms include the timing of daily cycles of alertness, sleep and wake, mood, appetite, hormone regulation and body temperature. In some animals, they have a quite different task: magnetoreception, which is the ability to detect the Earth’s magnetic field for the purposes of finding direction – an underlying mechanism for orientation in, for example, birds, bees and cockroaches.
But it turns out that people have nonvisual photoreceptors too. With the discovery of light-sensitive retinal cells in addition to rods and cones in mammalian retinas, it has become obvious that humans must use some sort of nonvisual pathway for at least some of the control of behavior and function. For example, pupil size and circadian rhythms vary with changing light, even in functionally blind humans who have lost all rods and cones due to genetic disorders. Recent research with rodents at Johns Hopkins University suggests that these nonvisual pathways can even regulate mood and learning ability.
It turns out that these photoreceptors in humans go far beyond the eyes and that, just like animals, they are found in our skin, subcutaneous fat, central nervous system and host of other areas in our body. Because the human skin is exposed to a wide range of light wavelengths, one recent study investigated whether opsins, the light-activated photoreceptors that mediate photoreception in the eye, are expressed in the skin to potentially serve as “photosensors”. They showed that four major opsins are indeed expressed in two major human skin cell types: melanocytes and keratinocytes and that these opsins are capable of initiating light-induced signaling pathways to the rest of the body.
Another recent study at Johns Hopkins University discovered melanopsin inside blood vessels. Melanopsin is another one of the photoreceptors used in retinal nonvisual photoreception. The researchers found that this light-sensitive protein can regulate blood vessel contraction and relaxation, and can also be damaged by exposure to blue light. Interestingly, melanopsin tends to be much weaker and more susceptible to this damage when fat-soluble Vitamins A and D are deficient.
Another recent finding backs up the fact that it is not only light falling on our eyes which determine our “circadian rhythms” – the body’s internal clock. In this study, it was shown that shining a bright light on the skin (in this case, behind the knees) has the same effect as shining light on the retina when it comes to regulating our 24-hour circadian clock. Scientists suggest that one reason that humans have circadian rhythm photoreceptor on their skin is that when light falls on blood vessels near the skin, it increases the concentration of nitric oxide in the blood, which can significantly shift the circadian clock. This should be especially important to you when you learn this: blue light can penetrate skin as deep as blood vessels, which means that artificial light on your skin can directly affect your circadian rhythm.
Then there’s a photoreceptor protein called “neuropsin”, which is primarily found in the retina but is also located in the skin and is another of the light-sensitive pigments that have been found to help run the body’s master clock. Neuropsin responds to UV-A and violet light, while melanopsin seems more sensitive to blue and red light. This may partially explain why going out into the sun during the day (which activates neuropsin) may work so well for regulating your circadian rhythm.
Finally, it seems that these photoreceptors strongly interact with hormone production and fat burning too. In one study, researchers put some fat cells under lamps giving off visible light that simulated the sun for four hours and kept other samples in the dark. After two weeks, the fat cell groups showed remarkable differences, including fewer lipid droplets (these are the organelles that store fat), compared the cells that didn’t get any light. This means that exposure to adequate sunlight (on both the skin and the eyes) could actually cause your cells to store less fat – and based on a number of compelling studies, artificial light (especially blue light) may have the complete opposite effect!
If you want to take a deep dive into how profoundly light can interact with the skin, you should check out work of my former podcast guest Dr. Jack Kruse, who even talks about how light exposure to the eyes and the skin affects your carbohydrate sensitivity, thyroid activity, hormone production and much more.
Fascinating, eh? Alright, back to the light-hacking tips…
#9: Use Driftbox For Your TV.
The Driftbox is a small box that you plug into your TV. It removes a percentage of blue light from the content you watch, and allows you to view the TV screen at night with far less artificial light exposure. You can set how much blue you want to take out. For example, you can set it to remove 50% (or any percentage in increments of 10%) of all blue light over a period of one hour (that way, the transition is seamless and virtually unnoticeable if you’re watching a movie at night).
#10: Don’t Overuse Sunglasses.
Unless I’m trying to avoid snow blindness from a day of snowboarding on a glaring bright white slope or I’m at a windy beach getting sand blown in my face, you’ll rarely find me sporting sunglasses. Why? Our bodies are designed to be able to perfectly cope with sunlight. The retina in your eyes actually registers how bright it is, then secretes specific hormones to keep you safe from the sun. Specifically, sunlight stimulates your pituitary glands, via the optic nerve, to produce a hormone that triggers the melanocytes in your skin to produce more melanin, which allows you to tan and offers some protection from excess UV radiation. When you wear sunglasses, less sunlight reaches the optic nerve, and thus less protective melanin is made and the higher the risk of a carcinogenic and uncomfortable sunburn. However: if you don’t happen to have a set of blue light blocking glasses handy, there can be an advantage to “wearing sunglasses at night”, especially while driving: car headlamps are notorious sources of concentrated blue light from LED!
#11: Use Photobiomodulation Daily.
Photobiomodulation therapy involves using light of all wavelengths, including visible light, ultraviolet and red near-, mid- and far-infrared wavelengths to combat the effects of artificial light and to also elicit some surprising research-proven health benefits for the entire body. For example, blue light therapy has been shown to be good at relieving joint pain, although it can be harsh on the eyes and the circadian rhythm if you overdo it. Red light has a host of research proving it’s efficacy for relieving inflammation, balancing blood sugar, lowering fat deposition, improving macular degeneration, assisting with melatonin production, increasing blood flow to the brain, building stem cells in bone marrow, and even enhancing kidney and thyroid function. Perhaps most surprisingly, Olympic athletes are now using red light therapy devices as a performance-enhancing aid to increase time to exhaustion. One of the most commonly used wavelengths of light in photobiomodulation is near-infrared, which begins at about 750 nanometers (nm) and goes all the way into 1,200 nm. In the lower range, near-infrared penetrates beneath the skin, and at the high range, deep into the body, resulting in a significant release of nitric oxide and stimulation of mitochondrial pathways that assist with ATP production. Far-infrared is another spectrum frequently used in photobiomodulation, especially in the form of heat lamps or infrared saunas. It is absorbed by the water in your body, which is why it cannot penetrate as deeply as near infrared, but also has significant healing effects on the body, especially if you are well hydrated on some form of “structured water” while using it (read Gerald Pollack’s book “The Fourth Phase of Water” for more on this).
A word of warning: there appears to be a “Goldilocks effect” when it comes to photobiomodulation: most photobiomodulation devices use a power density that is between 10 and 20 milliwatts per square centimeter. That is the equivalent light dose of 1 joule per 100 seconds, and since approximately 10 joules is considered to be a therapeutic dose of light, you really don’t need to use photobiomodulation for much more than 20 minutes per day (depending on the power of the device you use and your distance from the device). In addition, all light emits a frequency, and it appears that the ideal frequency is 10-40 hertz – with higher frequencies potentially causing a negative biological effect. I personally use a photobiomodulation panel of clinical-grade red and near-infrared light called a JOOVV (placed near the standup desk in my office) for 20 minutes per day, along with a head-worn device called a “Vielight” (code: GREENFIELD) for 25 minutes every other day, and finally, a far infrared sauna for 30 minutes three times per week.
Ultimately, you should now realize how profound an impact light has on your biology, why sunlight can regulate hormones and metabolism to allow you to stay lean and healthy, while artificial light can do the opposite, and the best way to “use light” to your metabolic advantage. I hope this has been helpful to you. Do you have questions, thoughts or feedback for me on any of these light hacking tips you’ve discovered? Leave your comments below and one of us will reply!