A couple weeks ago - I posted this article on the Sunshine Bill - and it sparked a lot of emotions (from people who wanted it to pass - and those who didn’t).
The article also created a lot of questions like: What about light boxes? What do I do if I can’t get morning sun in the winter as is? Wouldn’t a light box be a better alternative to the sun coming up too early in the summer?
Some people even got downright nasty with me…….but what’s the saying….”Don’t shoot the messenger”….?
Another thing that came out of this is that I got invited on a couple of podcasts to talk about this and debate people who are in favor of this bill passing, and it made me think: What’s one thing people universally don’t want? Oh yeah - to gain weight (well not everyone - but a lot of my community 😂).
So today is a follow up post that will explain how this bill potentially raises obesity risk for millions of people (with the studies to back it up), why a light box won’t fully fix the issue & circadian living in less than ideal latitudes.
But do not fret - because I will also offer solutions.
And a quick reminder before we jump in: we can still stop this bill. Click here to read the first article with action steps you can take to make your voice heard (and don’t be afraid to bug your legislators again, because “allegedly” - they work for us).
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This is where there is no debate when you look at the literature: When you push a whole country’s morning light later, you are changing the way their metabolism operates. The research on this is not new at all, and is one of the most consistent findings in circadian biology. That’s why I’m saying this off by stating it is not really a debate.
So let’s dive in to some of that science….
This is foundational (and completely overlooked by the average person): Light is information, and it is the single most powerful signal your body uses to figure out what time it is, and the primary driver is light going through your eyes to your brain (which is where your “master clock” lives).
You have a special set of cells in your retina, called melanopsin cells, whose entire job is to sense light and report it, not so you can see, but so your brain can set its clock. Those cells wire directly into the master clock in your hypothalamus, the same region that controls hunger, body temperature, and blood sugar.
A 2024 review in Nature Metabolism laid out just how far that wiring reaches. Light coming through those cells helps regulate glucose handling, fat breakdown, heat production, and appetite, some of it through your clock and some of it through direct pathways that bypass the clock entirely (Rao and Xue 2024).
So when I say morning light is a signal for your metabolism - this is where that comes from. Your metabolism has a light sensor, and it’s dependent on the morning sky.
This is the part that all of the “we just want longer days” people simply don’t understand.
Your body is not the same metabolic machine at 8am and 8pm. Your insulin sensitivity, your glucose tolerance, and your energy expenditure all follow a daily rhythm, and that rhythm is built to peak earlier in the day (Poggiogalle 2018). You handle a meal better in the morning than the same meal at night, because your metabolism follows a circadian rhythm that is set by morning sunlight.
Morning light sharpens & refines the natural cortisol pulse you’re supposed to get right after waking, the one that gets you moving and primes your blood sugar for the day. In controlled testing, bright morning light raised that cortisol rise compared to dim light (Petrowski 2020). That is not the “bad kind” of cortisol - that is the signal your metabolism depends on to really run efficiently.
When you force someone to start their day in darkness - the “start” signal comes late, or weak, or not at all. You could say that the engine idles.
As I mentioned in the beginning of this article: This is not theory, and we have known about light and metabolism for years. It’s just not something you can bottle up and sell - so it doesn’t get the airtime it deserves.
This is also why every single custom plan I create for my clients - and every single program I teach AND free ebook I create out starts with light.
Shoot - I built an entire app around this, because I know how fundamental this is for nearly every single health marker.
Where the rubber meets the road: Researchers at Northwestern tracked 54 adults for a week with wrist monitors measuring their real light exposure alongside their food logs. For every hour later that a person’s bright light landed in the day, their BMI went up by more than a full point, and it held after accounting for how much they slept and how much they ate (Reid 2014).
In another study - researchers measured the light first and the body change later. Over 1,000 adults, tracked for almost two years with actual light sensors. More morning light predicted losing body fat over time, and leess morning light predicted gaining it. (Obayashi 2016).
And this study scales to the size of a country. In a study of nearly 89,000 people wearing light sensors, brighter days and darker nights predicted a lower risk of dying, and the effect was strongest for cardiometabolic death (Windred 2024). Darker days are not neutral at all.
If you’ve followed my work, you know I don’t think weight is entirely a willpower problem, and nothing shows that better than what happens when you break the timing while keeping the food identical.
In one of the cleanest experiments we have, researchers pushed 10 adults about 12 hours out of sync with their internal clock. Leptin, the hormone that tells your brain you have enough fuel, dropped 17 percent. Blood sugar climbed even as insulin climbed, which is the exact pattern of a body losing control of its glucose. Some subjects reached prediabetic glucose levels in days. Not from junk food - from timing (Scheer 2009).
It shows up in when you eat, too. In a tightly controlled trial where food, sleep, and activity were all held constant, eating late instead of early raised hunger, lowered energy expenditure, and shifted fat tissue toward storage. The late group burned less and stored more, on the same calories (Vujovic 2022). Circadian misalignment also drags on the appetite hormones themselves, tilting ghrelin, leptin, and fullness signals toward eating more (Chaput 2023).
Here is another study that reflects how people are really living these days (similar to shift workers with dim days and bright nights): When researchers compared shift workers to day workers, the shift workers did not eat more. Their calories were basically the same, and yet shift work is a known driver of obesity and diabetes. (Bonham 2016).
What does this really show us? When you move the light and misalign the clock - the body gets heavier eating the same food.
Convinced this bill is a bad idea yet? Let’s continue (and I will explain why you can’t fully hack it with a light box)….
Permanent daylight saving time steals an hour of your morning (the time we have the most data showing importance for health) and it pushes your whole light pattern later, which means more light hitting you in your biological evening, and that light is not harmless either.
One single night of sleeping under moderate light, about the brightness of a dim lamp, was enough to raise people’s overnight heart rate and worsen their insulin resistance by the next morning (Mason 2022). In the large population data, brighter nights tracked with a higher risk of type 2 diabetes, and the size of that jump rivaled the gap between low and moderate genetic risk (Windred 2024, diabetes). You cannot out-genetics your light environment.
So permanent DST hits you from both ends: Dimmer mornings when your metabolism needs the signal, and brighter evenings when it needs the dark.
I already know the conclusion many people will come to (mainly because people have been very argumentative with me in my comments with this rebuttal 😂): “Buy a 10,000 lux light box, sit in front of it for 20 minutes, problem solved.”
Here’s the problem with that logic (and it shows that people are truly unaware of how sunlight really works with biology): Sunlight is full spectrum, and your body is built to read all of it. A light box hands you a load of flickering blue light and calls it a replacement, and it is missing the exact wavelengths that do the metabolic work.
Start with red and near-infrared. These are the wavelengths that reach your mitochondria, the tiny engines inside your cells that actually make your energy (oversimplification, but stay with me here). Inside them sits an enzyme called cytochrome c oxidase, and when red and near-infrared light hits it, your cells respond by making more ATP and water. That is your cellular power plant running on specific colors of light. Sunlight is loaded with red and infrared, and a blue light box gives your mitochondria almost none of it.
Dr. Glen Jeffery has done the most work around this topic that I find fascinating when it comes to metabolic health and mitochondria (my friend Dr Sara Pugh has two excellent interviews with him on her channel). His work shows just how opposite the two ends of the spectrum really are. In his lab, red light around 670nm ramped up mitochondrial energy production while blue light near 420nm suppressed it, and the two shifted blood sugar in opposite directions, red pulling glucose down and blue pushing it up. Then he showed it in people: just 15 minutes of 670nm red light before a glucose drink cut the blood sugar rise that followed by almost 28% over the next two hours. Sit with that for a second. The red end of sunlight your light box leaves out is the part that helps your cells pull glucose down, and the blue light it blasts at you is, on its own, the part that pushes glucose the wrong way.
Then there’s UV, and this is the one people get twisted, because they assume UV is only about vitamin D, and it is so much more than that (UVB = vitamin D... UVA is a very important metabolic signal).
When UVA hits your skin, it releases nitric oxide from stores sitting in the skin, widens your arteries, and lowers your blood pressure, completely independent of vitamin D. And it holds at scale: in a study of over 340,000 people, more sun exposure meant lower blood pressure, even after accounting for temperature. UV on the skin (and eyes) also switches on the POMC system and raises beta-endorphin, and POMC is the same melanocortin machinery your appetite and leptin signaling run through.
In 101 men, the brain made the least serotonin in winter, and serotonin production climbed with the hours of bright sunlight they got. Serotonin, nitric oxide (which is CRUCIAL for circulation), beta-endorphin, these are signals your body evolved to pull from real sunlight, and they feed mood and metabolism at the same time. A light box gives you zero UV.
99% of light boxes run heavy blue, and a lot of them flicker. As a clinician, I watch people buy them, use them faithfully, and end up feeling dysregulated, which looks like trouble sleeping, anxiety, and that “too much coffee” feeling.
There is one kind I’ll actually recommend, because it lets you blend in red and dial the brightness (and no flicker) instead of blasting pure blue. But even the good ones can’t give you UV or meaningful infrared. So even the best device on the market is a partial signal that ultimately falls short.
So when someone tells you a light box solves this, hear where it’s coming from: it’s coming from people comparing lux numbers who don’t understand how these different wavelengths actually talk to your mitochondria and your metabolism. They’re measuring brightness and missing the entire spectrum.
Now, don’t stress. I’m still going to give you what to do, and some of it can help (I do work with hospital workers, EMTs and shift workers, so there are some strategies that can help). But my point is that a light box is not a substitute for the morning sun.
The free version already exists, it’s full spectrum, and this bill is moving it out of reach for millions of people.
And the solution for the sun coming up at 3am or 4am for a few weeks in the summer? What my Alaskan and Swedish clients have been doing for years: Blackout curtains (they are cheap & effective).
The mechanism studies show light wiring straight into the metabolic control centers of the brain, and lab experiments show that breaking the timing drops leptin and raises blood sugar on identical food. The cross-sectional data, the two-year longitudinal data, and the 89,000-person population data all point the same direction. And the one intervention trial that added morning light to overweight women lowered their body fat and appetite with no diet change at all (Danilenko 2013).
When every kind of study, from the cell to the population, points the same way, we ned to pay attention. The sleep and circadian scientists already reached this conclusion, which is why they lined up publicly against permanent DST in the first place.
The only real debate left is whether the people writing the law will look at the biology before they lock it in, or after.
Whatever Congress decides, tomorrow morning is still yours. Get outside in the morning - even for a few minutes, even when it’s gray. Especially when it’s gray, because an overcast morning outdoors still buries anything happening inside your house. Give your eyes the sky before the screen.
That one habit does more for your metabolism than almost anything you can buy.
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Remember: the free part starts tomorrow, and no one can legislate it away!
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