Light is Right

Also see:
10 Tips for Better Sleep Quality
Using Sunlight to Sustain Life
Red Light Improves Mental Function
Light as Medicine? Researchers explain how
Red Light and Near-Infrared Radiation: Powerful Healing Tools You’ve Never Heard of
PUFA, Aging, Cytochrome Oxidase, and Cardiolipin
Blue Light, Cytochrome Oxidase, and Eye Injury
Get a “Chicken Light” and Amp Up Your Energy!

The Therapeutic Effects of Red and Near-Infrared Light (2015)
The Benefits of Near Infrared Light
Blue light has a dark side
Tuning the mitochondrial rotary motor with light

-Consult a medical professional regarding all things related to your health.

“When I moved from Mexico, first to Montana and then to Oregon in 1966, I became very conscious of how light affects the hormones and the health. (For example, in Montana I experienced an interesting springtime shedding of body hair.) Many people who came to cloudy Eugene to study, and who often lived in cheap basement apartments, would develop chronic health problems within a few months. Women who had been healthy when they arrived would often develop premenstrual syndrome or arthritis or colitis during their first winter in Eugene.

The absence of bright light would create a progesterone deficiency, and would leave estrogen and prolactin unopposed. Beginning in 1966, I started calling the syndrome “winter sickness,” but over the next few years, because of the prominence of the premenstrual syndrome and fertility problems in these seasonally exacerbated disorders, I began calling it the pathology of estrogen dominance. In the endocrinology classes I taught at the National College of Naturopathic Medicine, I emphasized the importance of light, and suggested that medicine could be reorganized around these estrogen-related processes” -Ray Peat, PhD

“Very bright incandescent lights are helpful, because light acts on, and restores, the same mitochondrial enzymes that are governed by the thyroid hormone. In squirrels, hibernation is brought on by the accumulation of unsaturated fats in the tissues, suppressing respiration and stimulating increased serotonin production. In humans, winter sickness is intensified by those same antithyroid substances, so it’s important to limit consumption of unsaturated fats and tryptophan (which is the source of serotonin). When a person is using a thyroid supplement, it’s common to need four times as much in December as in July.” -Ray Peat, PhD


Changes in the seasons have significant effects on our body function. Why do I feel depressed, have worse PMS, and poor energy during the winter? Why am I more prone to sickness when it’s cold and overcast outside? Seasonal changes, poor sleep quality, graveyard shifts, and hectic work schedules can take a toll on the body.

Exposure to darkness has a major effect on our health. Light has a multitude of positive effects on our hormonal systems and the way we feel. Avoidance of the sun is recommended to “avoid” cancers of the skin. Such recommendation and modern habits create a society that is experiencing symptoms of light deficiency. This blog explores the topic.

Light It Up
It’s no coincidence that places like Texas, California, and Florida have large populations. Most people want to live in areas with a warmer climate as opposed to the frozen tundra of the likes of Green Bay, WI or Regina, Saskatchewan. Generally, humans enjoy the energizing warmth of the sun, the light it provides, and how it makes us feel. Light exposure and warmer temperatures support metabolism, mood, and optimal body temperature maintenance. Because of improved cellular energy production, our capacity to handle stress improves in relation to our exposure to light.

In comparison, the cumulative effects of darkness over an extended period of time reduces our ability to handle stress. Darkness is a stress because it impairs energy production and is associated with a rise in a variety of inflammatory substances some of which compensate for decreased energy production.

Red light from sunlight (and bright incandescent light) helps cells produce energy, synthesize protective steroid hormones, and reduce the stress hormones that result from darkness and low energy production. Since light exposure improves the metabolic rate and darkness does the opposite, we’d expect that low metabolism and stress related symptoms would surface more during the winter than during the summer months in some people.

Summer v. Winter
During the summer, days are longer and temperatures are higher than during the winter. The summer weather encourages people to do more activities outdoors. The immune system is strongest in the summer as a result. In all aspects, the opposite can be said regarding the winter months.

During the winter, the body is more prone to symptoms of low resting metabolism like seasonal depression (seasonal affective disorder), weight gain, PMS, anxiety, food cravings, fatigue, poor sleep quality, and colds/flus which come about due to lowered temperatures and less light exposure associated with winter. Flu season just happens to occur during the winter when the metabolism slows and immunity is weakest. Endotoxin (lipopolysaccharides), defensive toxins made by gut bacteria, enter the bloodstream during stress (darkness), aging, and malnutrition and can be blamed on symptoms associated with colds and flus. The medical use of antibiotics lowers endotoxin (and estrogen) and the symptoms associated with these issues.

Adrenal stress hormones like adrenaline and cortisol rise during darkness. These stress chemicals suppress metabolism, lower immunity, decrease blood flow to the intestines, and contribute to storage of belly and back fat. Lowered vitamin D production may also play a role in increased susceptibility to infection during winter and prolonged darkness. Vitamin D is obtained in the diet from animal foods and formed endogenously from cholesterol in the skin when exposed to sunlight.

Light deprivation induces a progesterone deficiency allowing cortisol, aldosterone, estrogen, and prolactin to act unopposed creating PMS symptoms, other women’s issues, fatigue, mood change, and weight gain. The darkness causes chronic rises in melatonin and adrenaline as well. Consistently high melatonin has been shown to inhibit progesterone production and lower thyroid hormone output. Melatonin and adrenaline’s liberation of stored PUFA during darkness further poison energy production. This situation mimics that of chronic stress and its metabolic suppression and body temperature lowering effects. The resulting low progesterone, low thyroid, and high inflammatory mediator state doesn’t allow us to resist stresses creating the groundwork for health issues.

The symptoms and markers (high TSH) of thyroid deficiency do seem to appear more so during the dark winter than summer. Populations of the northwest and northeast United States likely experience these season related metabolism changes more so than individuals living in Arizona or Southern California.

Modern Life Mimics Winter
Due to concerns about skin cancer, many are told to avoid sun exposure. Changes in the diet particularly the change toward more consumption of polyunsaturated fatty acids, (which are found in restaurant foods, processed/boxed foods, and “health” foods like grains, beans, nuts, seed, fatty fish, above ground vegetables, seed oils, fish oils, nut butters, and vegetable oils) are to blame for the increase incidence of skin cancer. Some populations develop melanomas on parts of the body (bottoms of feet) where the skin isn’t exposed to the sun. The use of some sunscreens predictably increase likelihood of skin cancers.

Our ancestors likely had more sun exposure than we do as well as far less exposure to anti-metabolic food stuffs. Modern life has manipulated the summer v. winter scene that I have discussed here as even during the summer months people aren’t getting light exposure.

The typical nine to five worker often suffers from light deficiency as the day often entails getting up early, rushing out of the house to make it to work, sitting in a car on the commute, then sitting inside all day at work under fluorescent lighting, traveling home, and then heating up a prepared meal and watching TV.

Children these days aren’t immune to this same scenario as they are more likely to play Xbox 360 or be on the internet after school than ride bikes and play outside. Whether it’s winter or summer really doesn’t matter because people aren’t outside anyway, and it’s important to note that indoor fluorescent lighting (rich in blue light) unfortunately has the same effects as darkness on the cellular energy production.

Sleep – Friend or Foe?

“For many years, it has been known that the death rate increases during the winter months and also increases at night (winter or summer). Most deaths occur just before dawn when the body is in its least efficient state.” -Ray Peat, PhD

For many, night time is a very stressful time. The symptoms associated with a cold, flu, or infection are often noticeably worse at night than during the day. Immune function at night (and throughout winter) suffers as the metabolic rate falls and stress substances rise to compensate. Without ample energy, the body cannot fight the presenting infection properly and symptoms emerge more forcefully.

People with low metabolic rates (i.e. seniors) often pass away in their sleep because of how stressful it is irregardless of the season. Grave yard shift workers who I have worked with often have a terrible time with weight management and are very low energy despite the attempt to “catch up on sleep” during the day. Those with inflammatory conditions like rheumatoid arthritis often awaken with the worst pain they experience the entire day, and the pain centers where the tissue temperature is the lowest – in the hands and feet. This doesn’t happen by coincidence.

Blood sugar falls during sleep especially if the person cannot store glycogen; carbon dioxide production suffers; circulation is poor; and body temperature falls. Stress mediators are produced (like cortisol, adrenaline, aldosterone, serotonin, melatonin) in the attempt to maintain the metabolism, blood sugar, and circulation just as they are during the waking hours. This results in poor sleep quality, inflammation, and in extreme cases death. In essence, sleep is not peaceful especially when the metabolic rate is poor.

Protection from Darkness
Our best protection against the stress of darkness is youthful sleep. Healthy children can seemingly sleep through a nuclear bomb because they have a high metabolic rate and optimal body temperature that keeps the aforementioned inflammatory mediators down & CO2 up allowing the body to fully relax and avoid the stress of darkness.

A very high metabolic rate allows us to shutdown, sleep deeply, and awaken refreshed. This degree of sleep quality and energy production is possible throughout life if a thyroid supportive diet and lifestyle is utilized. Much of what people are being told to eat and supplement with unfortunately does not have this goal in mind.

“Many health food stores are now selling melatonin, to induce sleep and “prevent cancer.” They have taken some information out of context, and don’t realize how dangerous melatonin is. It makes the brain sluggish, causes the sex organs to shrink, and damages immunity by shrinking the thymus gland. It is the hormone of darkness and winter, and is produced in the pineal gland by any stress which increases adrenalin. Adequate sun light suppresses the formation of melatonin.” -Ray Peat, PhD

Melatonin is an anti-metabolic, inflammatory mediator, and body temperature lowering substance that rises in response to darkness. People often supplement with melatonin to improve sleep quality not knowing of the real effects of such a strategy.

Protective Diet and Lifestyle

If darkness is as a stressor, and melatonin’s rise along with other inflammatory markers occurs during the night which serve to suppress mitochondrial energy production, this modifies melatonin’s status as the “sleep hormone” into another part of a nocturnal inflammatory cascade.

Bright light therapy for seasonal affective disorder, the bipolar, and the depressed decreases melatonin and improves thyroid function lowering symptoms associated with each respective dysfunction. This type of therapy would be beneficial for anyone with a “light deficiency.” The reduction in trytophan rich foods (egg whites, muscle and organ meats, whey protein, some fruits), particularly later in the day, in favor of more gelatin rich proteins reduces the nocturnal formation of serotonin and melatonin resulting in better sleep quality and duration. This dietary strategy mimics the effect created by the bright light therapy.

Balanced blood sugar is key to good sleep as is the ability to store glycogen. The brain, liver, and muscle are the primary sites where sugar is stored as glycogen. A healthy person has upward of eight hours of stored glycogen available which is ideal for use when sleeping when blood sugar drops. The ability to store glycogen depends on the health of the metabolism. Fructose from ripe fruits encourages glycogen storage. The chronic stress and hypoglycemia that results from a low metabolism often leaves a person with depleted glycogen stores and less than optimal sleep quality and duration.

Milk/sugar/salt consumed before bed helps to improve sleep quality in many people from my experience. It does so by improving circulation, lowering aldosterone/cortisol/adrenaline, and helping balance blood sugar. If you awaken frequently during the night, this combination can help put you back to sleep as will a ripe fruit or glass of fruit juice. The anti-stress and thyroid-promoting effects of these recommendations improve sleep quality.

Here is a word from Ray Peat, PhD on what a metabolism-protective diet entails.

“This would emphasize high protein, low unsaturated fats, low iron, and high antioxidant consumption, with a moderate or low starch consumption. In practice, this means that a major part of the diet should be milk, cheese, eggs, shellfish, fruits and coconut oil, with vitamin E and salt as the safest supplements. It should be remembered that amino acids, especially in eggs, stimulate insulin secretion, and that this can cause hypoglycemia, which in turn causes cortisol secretion. Eating fruit (or other carbohydrate), coconut oil, and salt at the same meal will decrease this effect of the protein. Magnesium carbonate and epsom salts can also be useful and safe supplements, except when the synthetic material causes an allergic bowel reaction.” -Ray Peat, PhD

Anything that lowers the metabolic rate will affect sleep quality. A workout late in the day often disrupts sleep. Exercise suppresses metabolism, affects blood sugar, increases blood viscosity making clots more common, and raises stress hormones in a similar way that darkness does.

“Since the blood becomes more concentrated, viscous, and clottable during the night (especially during long winter nights), the risk of a heart attack or stroke would probably be reduced by drinking orange juice before getting out of bed (and at bed-time), to dilute the blood and decrease adrenaline and the free fatty acids, which contribute to the increased tendency to form clots in the morning.”
-Ray Peat, PhD

Serotonin, PUFA, estrogen, lack of light exposure, chronic stress, and endotoxin are main players in lowering the metabolic rate because of the stress they create. The health of the liver is important in destroying endotoxin, PUFA, and estrogen and in maintenance of the metabolism. The liver requires protein, b-vitamins, thyroid, and sugar to function well. Regular elimination takes stress off of the liver and lowers serotonin, estrogen, and endotoxin.

Digestible foods should pervade the diet and be combined in a way that balances blood sugar – meals should should contain a carbohydrate source and a protein source. Protein intake from animal sources should be a minimum of 70g of protein daily. Carbohydrate intake should often be 1.5 to 2 time higher than protein intake to energize the body and blunt the stress response and the inflammatory, anti-mitochondria mediators that accompany it.

Consider avoidance of fluorescent lights and overnight shifts when possible and increase sun exposure or supplement with incandescent light during the winter or during times when sun exposure isn’t possible due to work or other commitments. Short bouts of summer sun or bright light supplementation (5 to 20 minutes) several times daily are beneficial to health, reduce the stress reaction associated with darkness, and limit chances of skin damage. Sunburn should be avoided.

Consult a medical professional regarding all things related to your health. FPS coaches a 12 to 16 week nutrition course based solely on the methodology of Ray Peat, PhD. Please click here for more information.

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6 Responses

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  1. Fernando says

    Hey Rob,

    According to Peat’s philosophy, would it be beneficial to do some light therapy before bed?

  2. Team FPS says

    “In fall and winter, use very bright incandescent lights daily from sunset until bedtime.” -RP

    If you are “light deficient” during spring and summer, I’d suggest using the strategy year round.

  3. Asa J says

    I have heard Peat say that bright light uses up vitamin A “quickly.” How much vitamin A is consumed being under 500w light for 6 hours of the day? I hear one person say “liver once or twice a week” and other people who take 100k IU of vitamin A per day. It’s so confusing! How does a person know how much to take?

  4. Team FPS says

    I can’t say directly how much vitamin A is needed when you’re around the light for 6 hours, but the presence of acne or dandruff are two signs of vitamin A deficiency to look out for.

    Thyroid hormone and vitamin A needs are closely linked. The rate of metabolism will determine the need for vitamin A and other nutrients. As the metabolism rises, so too does the dietary support needed to maintain that rise.

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