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You Are When You Eat

January 20, 2021

You’ve likely heard the phrase, “you are what you eat.”

It accurately suggests that eating low-quality, nutrient poor, or artificial food is a recipe for disaster. In the modern food environment, with its endless selection of junk, this is incredibly relevant.

But, we often forget the other half of the optimal nutrition equation—when you eat. In fact, one could argue this matters far more. Yet, it hardly receives the discussion it deserves, if any at all.

Turns out, light isn’t the only factor influencing our circadian rhythm. Food also has a massive impact and must be part of a lifestyle built around circadian synchronization.

Nature’s Rhythm

First, let’s take a deeper look at our circadian rhythm.

The term "circadian rhythm” was first coined by Franz Halberg to describe the cycle of biological processes lasting roughly 24 hours (1). The circadian mechanism is an important feature of most organisms, allowing them to adapt physiologic action to environmental signals for optimal function (2).

In mammals, this process is controlled predominantly by the Suprachiasmatic Nucleus (SCN), which is located in the hypothalamus and also drives peripheral clocks throughout the body.

The most significant cue for physiologic function has proven to be the light environment—i.e. the diurnal patterns of light and darkness and the sun’s daily/seasonal changes in wavelength. Consistent exposure to natural light sets our circadian clock and initiates function throughout the body. The absence of light—darkness at night—is a critical signal for rest, repair and regeneration.

However, when and what we eat are a close second in terms of importance to circadian synchronization. In fact, given that the entire food web begins with the sun (photosynthesis), you could argue they are almost one and the same.

Optimal Health = Circadian Synchronization

Nearly every physiologic process is intimately connected to the circadian mechanism and emerging science continually places circadian synchronization at the center of health.

Processes like metabolism, glucose, body temperature, cognitive performance, hormonal balance, immune function and mitochondrial activity all require circadian alignment to function optimally.

What does this mean? No matter how well you eat or how much you exercise, circadian synchronization always sits atop the hierarchy of optimal health. But, the inverse is also true—chronic circadian desynchronization is a sure way to dysfunction.

When we become desynchronized from our environment, our body loses its ability to initiate the correct biological functions. In the short term, this may look like fatigue, low energy, lack of mental clarity and poor mood. Over time, chronic desynchronization will always lead to more serious dysfunction and is a proven risk factor for any of the chronic diseases that are so prevalent today.

The Modern World

The modern world does everything it can to disconnect us from optimal circadian alignment.

The most obvious and ubiquitous way is artificial light from technology, LEDs, etc. which predominantly emit high energy, short-wavelength blue light. Naturally occurring blue light is present only in the early/late morning and stimulates wakefulness via cortisol. Exposure to artificial blue light at night initiates the same response and disrupts our circadian rhythm entirely.

But, we also have another factor working against us—our complex brains, which have created an environment of extraordinary accessibility to whatever food we want, whenever we want.

You may be wondering—how is that a problem?

Human evolution occurred in complete alignment with nature and for most of our history, we relied exclusively on the environment to meet our nutritional needs.

However, that model has been drastically altered—instead, we are able to obtain whatever food we want regardless of seasonality and location simply by taking a trip to the grocery store. While this may seem like progress, it’s a blimp in the history of human development and we aren’t optimized to consume foods that are not matched to our environment.

Not to mention, much of what we consume is artificial and chemically composed with no connection to nature and no business entering our body. Like artificial light, artificial food is extremely disruptive to the circadian mechanism and wreaks havoc at the cellular level. The result—you guessed it, eventual dysfunction and disease. 

To make matters worse, modern life has thrown one final challenge our way—meal timing, or lack thereof. In a 24/7 world, consuming food outside of daylight hours is entirely normal, if not encouraged. Unfortunately, this too creates circadian desynchronization with more serious consequences later on.

The Solution

So, how do we eat in a way that aligns with our circadian rhythm?

There are two factors to consider—what you eat and when you eat it. Let’s dive into both.

First, our environment and food should match—this means eating locally and seasonally, while avoiding artificial food at all costs. 

Today, there is a great deal of attention given to food quality and sourcing as part of a healthy diet—i.e. the rise of categories like organic, pasture-raised, grass-fed, and non-GMO. While these are important factors to consider, we often miss two of the most important—locally grown and seasonal.

There’s no doubt that it’s enjoyable to eat bananas in the winter or mangos in New England, but plants are a reflection of their light environment via the photosynthetic process. When and where a specific plant grows depends entirely on the availability of solar energy. Carbohydrates, like fruit and vegetables, are more available in warmer seasons/locations when solar energy is more abundant and less available in colder seasons/locations when solar energy is minimal. Think of food like a barcode, storing unique information from the sun.

We too are a reflection of our light environment and utilize the sun’s energy through direct exposure and by breaking down food into electrons and protons. Both processes are critical for our mitochondrial production of ATP (energy) as well as circadian synchronization.

As we break down food, our mitochondria read the barcode and decipher the unique information provided by the sun. When the information contained within food’s electrons and photons match our environment, our body can coordinate an optimal response. When the signals don’t match, energy output is lowered, inflammation is increased and dysfunction ensues.

As such, eating seasonally is a choice to stay in alignment with your environment and create an ecosystem for optimal function.

The best way to do this is to commit to buying local. The selection will be limited to what is available seasonally and the information contained within the products will always match your environment—win, win! Not to mention, you can learn a great deal from your local farming community.

Second, meal timing is critical—eat with the light!

When you eat and the environment you eat in are also important pieces of information. When the information matches, we are able to process and utilize nutrition optimally.

We were designed to eat during daylight hours, when we are most metabolically and hormonally active as well as when our mitochondria are producing energy most efficiently.

Rising with the sun and starting your day with a large breakfast, when hormones are primed to respond, is a great way to boost energy levels and process food optimally. As the day continues, gradually taper off meal size.

Finally, avoid food at all costs once the sun has set and try to finish eating at least three hours prior to going to sleep.

During daylight hours, our physiologic function is geared towards activity, energy production/expenditure and food consumption.

However, the nighttime is reserved for cellular repair and recovery.

Eating too close to bed or outside of daylight hours disrupts our circadian mechanism, which inhibits activation of critical repair processes. Chronic desynchronization and lack of cellular repair over time will inevitably result in dysfunction.

Consciously time your last meal to allow a gap of at least three hours before going to bed and make sure to leave the snacks behind. You will find you sleep better and wake up feeling refreshed and ready to take on the day.


The modern world has made optimal nutrition seem complicated, mysterious and unattainable. But, it doesn’t have to be—in fact, it shouldn’t be.

Our ancestors had it figured out long before we knew how to disrupt these natural processes and it was simple—eat seasonally, eat locally, and eat with the light. The rest will follow. 

See you in the field.



1. http://halbergchronobiologycenter.umn.edu/home/franz-halberg

2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2848671/



Medical Disclaimer: This content is for informational and educational purposes only. It is not intended to provide medical advice or to take the place of such advice or treatment from a personal physician. All readers/viewers of this content are advised to consult their doctors or qualified health professionals regarding specific health questions. Neither Dr. Monette nor the publisher of this content takes responsibility for possible health consequences of any person or persons reading or following the information in this educational content. All viewers of this content, especially those taking prescription or over-the-counter medications, should consult their physicians before beginning any nutrition, supplement or lifestyle program. Statements made on this website have not been evaluated by the U.S. Food and Drug Administration. Products sold on this website are not intended to diagnose, treat, cure, or prevent any disease.

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