Does blue light cause weight loss stall?

Coming from a nutritional research background I am only too familiar with the infamous weight loss stall and the protocols to combats this inevitable situation on any weight loss journey. Should you cut calories, increase calories, change macronutrients, exercise more or have a cheat meal? These are all solutions to the weight loss stall, some may work, some may not, but what if I told you there was unequivocal evidence to suggest that blue light is the main reason we all stall on weight loss diets, independent of the type of diet we choose to follow. It does not matter if you are looking to lose weight on keto, vegan, carnivore, CICO or any other dieting plan, if your light hygiene is not optimal, you will stall, struggle to lose weight and wreck your hormones.


Cortisol is our often wrongly termed “stress hormone”, however #context applied here as if we are running from a lion or missing office deadlines it will be rightly termed the "stress hormone"  Cortisol, like all hormones in our body, runs on a circadian cycle. This means that it has preferred times of the day it should be secreted and times when it should not be secreted. Cortisol is at its highest as we wake, the cortisol awakening response, and then slowly drops to a suppressed state post sunset. This is what cortisol’s circadian cycle should look like in a someone with a healthy circadian rhythm, the blue line.


When we disrupt our cortisol cycle, for example by exposing ourselves to blue light after dark, it can reverse as shown in the irregular curve in orange. This means we lack energy in the morning when we need it to wake up and have too much cortisol in the evening which causes us to be active when we should be winding down for sleep.

Light increases cortisol, specifically in the blue and green ranges. We now work in an artificially lit world 24/7, exposing ourselves to copious amounts of blue light, from riding into work on the train, working behind a computer under office lighting and watching TV and turning on our house lights after dark. These sources of artificial light are doing one of two things. Either keeping our cortisol levels chronically high which creates an environment primed for fat gain and weight loss stalls, or reversing its cycle. Reversing the cortisol secretion cycle will impair the production of melatonin (sleep hormones and antioxidant) and disrupt our sleep. Disrupted sleep creates more stress on the body, more stress means more cortisol and more cortisol means more fat gain or weight loss stalls. More cortisol also means more cravings for foods high in both sugar and fat, the optimal combination for weight gain.



Too much, too little cortisol productin also impacts other hormones involved in sustainable and healthy weight loss such as testosterone, estrogen and also thyroid function.

In today’s society the preferred time to train in the gym is after work. For cortisol this is the worst time to train. Placing stress on your body from high intensity training raises cortisol, but the blue light present in the gym will intensify this even further, disrupt your circadian rhythms and destroy the amount of good quality sleep you are getting that night. When training one should always bear in mind light and circadian rhythms, train during daylight hours where you can and keep your sleep healthy, manage blue light better and wear blue light blocking or filtering glasses in the gym to keep your cortisol levels in check. This is why you can eat your “perfect” diet and still not lose weight or hit a stall. By training at the wrong time of day you are allowing light to disrupt your cortisol cycles, disrupt your sleep and create an environment primed for fat storage or fat retention.


"Eating carbohydrates raises insulin levels which creates an environment ripe for fat accumulation"…or so some factions of the dieting community states. Whether this is right or wrong when it comes to light food always plays second fiddle. Studies have shown that exposure to non-native electromagnetic frequencies (nnEMFs) such as Wi-Fi, microwaves and blue light all increase secretion of insulin and raise blood sugar levels, independent of diet. Maybe we need to move away from the carbohydrate/insulin hypothesis and move toward a light/insulin hypothesis for weight gain. Both have their flaws and its seldom one cause when it comes to hormonal disfunction, its multiple factors, light as well as diet being two of them.

Circadian rhythms are in every cell in our body and the pancreas is no exception. The pancreas secretes insulin in response to carbohydrate intake or a nnEMF stimulus such as artificial blue light. The preferred optimal circadian cycle for the pancreas is the morning being the most insulin sensitive time and at night we are most insulin resistant. If you are stalling on your diet and include carbohydrate in your protocol you would be wise to stack your carbohydrate consumption in the mornings when your insulin levels are most primed to process this macronutrient and avoid them before bed. Light and darkness influences blood glucose levels and insulin secretion therefore its best to adhere to these natural cycles if you want to overcome a weight loss stall. Not eating at all after sunset is also a good idea for optimal sleep and lowered cortisol production. Remember the old adage, eat breakfast like a king, lunch like a prince and dinner like a pauper.

Sunlight for the win

Research has shown that sun light is a vital tool in everyone’s weight loss journey. One such study states:

"Even after controlling for all non-light exposure factors including food intake, sleep, activity, the influence of morning light on weight was considerable—it accounted for roughly 20% of the subject’s BMIs, meaning those with earlier light exposure weighed less."

Sunlight in the mornings also helps with weight loss and also cortisol regulation:

"...individuals who had exposure to sunlight in the early part of the day had decreased levels of cortisol later on in the evening".

Managing Blue Light to Correct Your Cortisol Levels

We do not have to power down our devices and throw away your iPhone to manage blue light. Simply blocking all blue and green light found between 400-550nm is enough to re-sync your circadian rhythms and cortisol cycles. Regular sun breaks and wearing blue light filtering glasses during the day when inside can help lower cortisol levels.

Correcting your cortisol cycle is the key to overcoming weight loss stalls. Controlling your cortisol levels through light management is the way to go. Below is a light of hacks to correct your cortisol cycle and overcome your weight loss plateau.


  1. Watch the sunrise each morning
  2. Get regular sun breaks throughout your day
  3. Wear blue light filtering glasses during the day
  4. Wear blue and green light blocking glasses after sunset
  5. Watch the sunset
  6. Turn your devices to night shift mode
  7. Use Iris or F.lux on your computers
  8. Power down all digital devices 1-2 hours before bed
  9. Install red light in your house
  10. Utilise a red-light therapy device around sunset and sunrise


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One thought on “Does blue light cause weight loss stall?

  1. avatar Bulet Kumar says:

    Such a good article !!!! this blog is also so helpful , keep the mind fresh and active.which is so needed in our life. After reading this article I got some more ideas about it. Thank you. this blog is also so informative and helpful about weight loss, you can check this

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