How Artificial Light Makes Us Fat
In this article, we will explore how your distorted relationship with light impacts your waistline and why leptin and melatonin lie at the center. By the end, you will understand why wearing blue light-blocking glasses will help you lose weight.
How Artificial Light Makes Us Fat
In contrast to modern society, our ancestors evolved in vastly different environments. We have polluted and distorted life's central elements: light, food, air, water, and magnetism. These environmental mismatches are the root cause of our failing health and vitality. Nothing is wrong with you, but everything is wrong with your environment.
What is Leptin?
Leptin is a master hormone produced by the body's fat cells. It's the architect behind weight management, fertility, immunity, and other essential body functions.
Think of Leptin as your bank accountant, who keeps a tab of your energy status. Money is measured or valued in currency, such as £ or $.
Most people in the health space think energy is measured in calories because that's what is on food, and humans are machines that burn calories. This needs to be corrected. It does not happen. There is no calorie receptor or transporter. Calories do not go anywhere. They do not exist in cellular respiration / cellular metabolism.
Instead, we use leptin to determine our energy status, which is aligned with body fat. The leptin level alone, which you can measure in a blood test, does not explicitly mean activity, as you will discover leptin requires sunlight to be activated and enter the brain at night, more specifically aligned with your circadian biology with melatonin.
Why Calories Don’t Matter As Much As You Think
As your fat stores swell, so does the power of leptin to whisper to your brain, explicitly targeting the hypothalamus with messages of energy abundance or scarcity. This triggers a cascade of responses—your appetite diminishes, your metabolism shifts into high gear, and your body becomes a furnace, incinerating excess calories into heat through uncoupling proteins in your mitochondria.
This leptin-mediated mechanism allows you to maintain a stable weight, regardless of whether you ate more calories this week or less. Most health experts still need to understand this.
What happens when there is no leptin signal? This is exemplified in those with anorexia that lack fat stores. These individuals struggle with low energy, cold extremities, and infertility as their body recognizes they do not have adequate stores to support pregnancy.
Leptin Resistance
Leptin resistance refers to impaired communication between adipose tissue and the brain. The body interprets leptin resistance similarly to a low leptin signal during starvation.
Consider the fuel gauge in a car akin to the role of leptin in our bodies. Just as the gauge informs you about the gas level, leptin signals the body's nutritional state to the brain. Suppose the gauge malfunctions, leaving you clueless about the fuel status. In that case, your response during a road trip might involve overfilling the tank, driving cautiously, and refueling frequently to compensate for the uncertainty. Leptin resistance mirrored this scenario, manifesting as relentless hunger and decreased energy expenditure, resulting in obesity. The brain perceives a state of starvation, even though fat reserves are plentiful.
Leptin resistance is illustrated by a person who eats little but gains weight regardless. They have no energy to exercise, and their weight will increase dramatically if they eat more. They are stuck between a rock and a hard place. Now, it is time to connect the inner workings of leptin with our light environment.
Our Light Environment
Our light environment dictates our leptin sensitivity and is, therefore, one of the most critical factors in weight loss. Light is a nutrient, much like food; the wrong kind can make us sick, while the right type can promote health. 93% of our time is spent indoors, representing evolutionary history's most significant alteration to solar exposure. Simultaneously, our light environment is polluted by toxic artificial light at night.
Melatonin’s influence on Leptin
Melatonin is the connection between light, leptin, and obesity. This is because melatonin regulates the circadian rhythm of leptin secretion in white adipocytes and synchronizes it with the expression of leptin receptors (leptin sensitivity) in the brain. In addition, the absence of melatonin also decreases insulin-stimulated glucose uptake in cells and glucose oxidation, resulting in fat storage(1). It's not surprising that a melatonin deficiency is associated with metabolic syndrome and type 2 diabetes(2).
As melatonin levels rise in the late evening and peak in the middle of the night, so do leptin levels(4). Melatonin acts directly on the hypothalamus to upregulate leptin receptors precisely when leptin peaks(2).
Exposure to blue and green light after sunset suppresses melatonin production, which has untold consequences for our health. What are our phone screens, laptops, and LED lighting systems rich in? Blue light.
Removing the pineal gland that produces melatonin in rats (PINX) results in leptin resistance(2). These rats develop hyperphagia and obesity over time(2). PINX rats do not respond to leptin injection, suggesting leptin resistance(2). The ability of PINX rats to activate the leptin pathway in the hypothalamus was compromised but restored upon melatonin treatment(2). Melatonin is required to maintain leptin sensitivity, independent of body adiposity.
Melatonin deficiency downregulates brown adipose tissue (BAT), which is a crucial mechanism for the body to regulate its weight and temperature(6). Optimal melatonin levels stimulate BAT growth and increase the number of mitochondria present and the expression of UCP1, which is essential for burning energy(3). Removing the pineal gland that produces melatonin reduces our bodies' thermogenic capacity(3).
The coupled actions of leptin and melatonin also regulate our adipocytes' immune function and inflammatory processes. This influences systemic inflammatory reactions throughout the body. A synchronized melatonin cycle protects us from metabolic "exhaust fumes" or oxidative stress by acting as a powerful antioxidant(3). It's also important to realize that as we lose weight and break down fat, toxins such as heavy metals stored in adipose tissue are released into the bloodstream. Thankfully, melatonin can also chelate heavy metals(3).
How can you protect yourself?
You must be more conscious about your light environment. Watching the sun rise and set daily is crucial to establishing healthy circadian rhythms. It would help to spend as much time outside as possible throughout the day and open the windows when working inside. Most importantly, you must avoid blue light after sunset.
Shut down your screens once the sun goes down.
Replace blue light bulbs with red light LEDs or incandescents.
Use blue light-blocking glasses.
In Summary: How Artificial Light Makes Us Fat
Our modern way of living is rife with evolutionary environmental mismatches. We need to catch up with nature and its laws. Bright days and nights have been replaced by continuous exposure to artificial blue light, and our health is paying the price. Resynchronizing your circadian clock and optimizing your melatonin levels will allow your body to regain leptin sensitivity and burn fat as it should.
References:
1. Alonso-Vale MIC, Andreotti S, Peres SB, Anhê GF, das Neves Borges-Silva C, Neto JC, et al. Melatonin enhances leptin expression by rat adipocytes in the presence of insulin. American Journal of Physiology-Endocrinology and Metabolism. 2005 Apr;288(4):E805–12.
2. Buonfiglio D, Parthimos R, Dantas R, Cerqueira Silva R, Gomes G, Andrade-Silva J, et al. Melatonin Absence Leads to Long-Term Leptin Resistance and Overweight in Rats. Front Endocrinol (Lausanne). 2018;9:122.
3. Guan Q, Wang Z, Cao J, Dong Y, Chen Y. Mechanisms of Melatonin in Obesity: A Review. International Journal of Molecular Sciences. 2022 Jan;23(1):218.
4. Chakir I, Dumont S, Pévet P, Ouarour A, Challet E, Vuillez P. Pineal melatonin is a circadian time-giver for leptin rhythm in Syrian hamsters. Front Neurosci. 2015 May 27;9:190.
5. Suriagandhi V, Nachiappan V. Protective Effects of Melatonin against Obesity‐Induced by Leptin Resistance. Behavioural Brain Research. 2022 Jan 24;417:113598.
6. Halpern B, Mancini MC, Mendes C, Machado CML, Prando S, Sapienza MT, et al. Melatonin deficiency decreases brown adipose tissue acute thermogenic capacity in rats measured by 18F-FDG PET. Diabetology & Metabolic Syndrome. 2020 Sep 21;12(1):82.