How to Live In Sync with Your Body Clock – Time Restricted Eating and Circadian Rhythm Explained

I talk a lot about how the modern world takes us out of sync with our natural rhythms. Recently, there has been a surge of research into Circadian Biology – the biology of time and internal biological clocks. We are now beginning to understand why the modern world seems to affect us in such a negative way. In this article, I will explain what I have learned and incorporated into my life to reset my body to its natural state.

Time Restricted Eating Explained

Time-restricted eating (TRE), on the surface, shares many characteristics with an idea many of you may be more familiar with known as intermittent fasting. Essentially, you are restricting the hours in which you consume calories from food and drink, but on a daily basis. The 2 Meal Day is a form of TRE, by skipping one meal you are in effect shrinking the time frame in which you consume food.

Recently, there has been researching into how foods affect us differently at different times of the day. It seems that it is better overall, to wait a few hours after waking to eat and to try and finish eating a few hours before bed.

The theory is that it’s not just the food that you eat that can have a negative or positive effect on your health and waistline, but also WHEN you eat these foods can have a big effect on biomarkers of health.

Your Circadian Rhythm Explained

In order to understand this properly, you need to first understand how your Circadian Rhythm (CR) works.

Virtually every living thing on our planet has evolved under the strong influence of a daily light/dark cycle which is governed by the sun. Daily changes in light and darkness combined with other environmental factors like temperature and humidity stimulate different processes in the body like digestion, blood pressure, body temperature and melatonin (the sleep hormone).

These daily environmental rhythms have led to the evolution of a 24-hour internal timing mechanism or circadian rhythm to enable living things to anticipate daily changes and to optimize fitness.

Fundamental to this 24 hour rhythm is the ability to acquire food when it is available and to store a portion of these resources for utilization during the rest of the day (i.e. the fasting period) without compromising fitness and vitality – in other words, there are certain times of the day when we are primed to digest and to utilise the food that we eat, and other times of the day where we are meant to be resting and repairing, drawing on stored energy (fat).

The recent research that has been done to date suggests that we want to incorporate lifestyle habits that are in sync with our circadian rhythms, to optimise health and fitness.

Things that take us out of sync with our circadian rhythm

In the modern world we now have access to many external stimuli that takes us out of sync with our circadian rhythm, below are the top five:

Artificial Light

For thousands of years, our daily habits and routines were determined by the sun. As the sun goes down the light changes, becoming more and more orange. The dimming of the light initiates melatonin secretion (the sleep hormone) in the brain, this was the cue for early Man to eat whatever had been caught that day and start preparing for sleep. The only light source after sunset was the amber glow of the fire.

This pattern is disrupted by modern life; the blue light that comes off screens mimics the light of full daylight, messing with the secretion of melatonin and ultimately affecting your sleep patterns.

By switching off your gadgets you are eliminating the risk of being exposed to the blue light. Some phones and laptops now come with a filter that can gradually make the screen more orange, these are definitely worth using.

The blue light isn’t the only reason technology can keep us awake at night. Checking social media feeds can keep the brain active and stimulated, as well as increasing the likelihood of overthinking and worrying about things as we are trying to drift off.

A Large Eating Window

Think about it, many of us eat within an hour of waking up and then continuously graze until right before bed. At best we are going 8/9 hours without eating (whilst we are asleep). That adds up to 16 hours of continuous eating, digesting and processing of food.

In early human history, food wasn’t continuously available, our bodies are primed to digest and utilise food for roughly an 8-10 hour time period, eating outside these hours will mean that digestion can take a lot longer and we will process fats and sugar inefficiently.

Inconsistent Bed/Waking Time

Your circadian rhythm is governed by routine. You need to be waking up at the same time every single morning, including weekends! Consistency optimises the quality and efficiency of your sleep.

As hunter-gatherers our entire day would have been governed by the sun going up and down, although this may seem like a long time ago, we are still governed by the same mechanisms. Early humans evolved close to the equator, which gets an even 12-hour day and night time period.

Anything that takes us out of sync with this light/dark cycle can have a profound effect on our mental and physical health. Winter periods in areas that are located in higher latitudes can have very long winter nights, where daylight only lasts a few hours. The rates of both suicide and depression go up significantly in these places.

Unfortunately, the modern lifestyle does not promote consistent sleeping habits, there are many things that take us out of sync with the natural light/dark cycle of the sun –  social media, Netflix, socialising with friends, the list is endless.

How to Live In Sync with your Circadian Rhythm

Go to Bed and Wake Up at the Same Time EVERYDAY

This is probably one of the most powerful ways to take control of your circadian rhythm. Optimise Sleep Blog Post.

Expose yourself to sunlight during the day

Reduced exposure to sunlight impairs circadian rhythms. To optimize your circadian rhythm, head outside and get some sunshine every day. In addition to helping your circadian system, this will also help you get a healthy dose of vitamin D, which has its own circadian rhythm-syncing properties! Vitamin D is crucial for optimal immune function, which we need to recover from chronic illness.

Time Restricted Eating

Researchers believe that eating within a restricted time period provides the digestive system the right amount of time to perform its function uninterrupted by a new influx of food, and enough to time to repair and rejuvenate, supporting the growth of healthy bacteria in the gut. It seems that we are primed to digest and utilised food effectively within an 8-10-hour time period.

In an ideal world, we would wait a few hours after eating to have our first meal and stop eating at least three hours before bed. I recently have put this into experimentation, I stop consuming all calories by 8pm, there has been a noticeable difference in the quality of my sleep and my energy levels in the morning. On the rare occasion that I do eat late, I get a “food hangover” the next morning – feel groggy, bloated and lethargic.

The 2 Meal Day is an effective way to incorporate TRE and reap the many benefits. (Study)

Movement

During the day our muscles are primed for activity. Moving as much as possible throughout the daylight hours is an effective way to keep our CR in check.

Optimise Your Gut Health

Emerging research indicates that intestinal cells and gut microbes have their own circadian rhythms that interact with our rhythms; this means that we can improve our gut health by taking care of our circadian system, and vice versa. Eating an anti-inflammatory, nutrient dense diet can normalize gut microbe rhythms and improve gut health. Taking probiotics like Symprove and eating natural yogurt, sauerkraut and kefir can help normalize your circadian rhythms by improving the health of your gut microbes.

Minimise the use of artificial light in the evenings

This is something that has had a profound effect on my life. As it gets later into the evening, I switch all technology off so that I am not exposed to the blue light from screens, the blue light mimics daylight and has the biggest effect on our CR. I also start to dim the lights in my house. By the time I go to bed, there is only very dim orange light from my bedside lamp and I use a candle in the bathroom to brush my teeth. I have developed my own pre-sleep routine that works perfectly for me.

How to live in sync with your body clock on a daily basis

I aim to do all these things on a daily basis. Of course, sometimes life throws you out of sync and you may not be able to follow the above practices 100% of the time, but as long as you are consistent 80% of the time, you should start to see and feel a big difference. In particular Time Restricted Eating seems to have a profound effect on our overall health and well-being, so it’s worth putting extra effort into sticking to a particular eating schedule.