By Melissa Blake, ND
Modern-day living has granted us access to an abundance of both food and artificial light, contributing to an endless opportunity for food production and consumption. The opportunity for overindulgence can lead to a number of health issues, including changes in sleep, mood, and energy, unwanted weight gain, heart conditions, memory issues, and digestive complaints.
The circadian diet offers a solution to these negative outcomes and is basically a way of aligning intermittent fasting with your circadian rhythm that takes into account not only what you eat, but when you eat.
What is the circadian diet?
While similar to intermittent fasting, the circadian diet divides a 24-hour day into two windows—one window when food is consumed and the other spent fasting (no food, only water).
The circadian diet emphasizes eating in sync with the body’s natural tendencies and instincts. This means eating during daylight hours during a window that is approximately 12 hours long and falls somewhere between sunrise and sunset, with evidence suggesting the earlier the eating window closes, the better.1
Eating in this way, with an emphasis on dietary timing, can help support the body’s natural circadian rhythm and contribute to overall health and wellness.1
The benefits of the circadian diet
The circadian diet, in part due to a positive impact on circadian rhythm, contributes to substantial benefits on sleep and metabolic health. This often means better energy, fewer cravings, blood sugar control, improved digestion, and weight loss.1
When done properly, the circadian diet is a safe and effective way of eating, and modifications can be made to suit almost any lifestyle, cuisine, or dietary preferences.
A sample day on the circadian diet
A day on the circadian diet involves more than just food. It starts with waking at a consistent time, ideally with the sun. After you wake, drink water or herbal tea to help meet your hydration needs. Follow that up with some gentle stretching or movement to help get the blood flowing and energize the body. Try to get outside within one hour of waking in order to help optimize your body’s internal clock.
Next, begin the 12-hour eating window within two hours of waking by literally breaking the fast with a well-balanced meal that includes protein, fruit, vegetables, and good-quality fat.
Aim to consume most of your calories earlier in the day, with a smaller meal to close the eating window. Ideally, you’ll want to stop eating two or more hours before bedtime in order to allow the body sufficient time for digestion.
“Aim to consume most of your calories earlier in the day, with a smaller meal to close the eating window. Ideally, you’ll want to stop eating two or more hours before bedtime in order to allow the body sufficient time for digestion.”
Close the window:
During the fasting window, which ideally starts early in the evening, drink water and herbal tea to stay hydrated. Consider a gentle movement routine and other calming activities to promote sleep, such as journaling, light reading, and breathing practices.
Another important aspect of the circadian health diet involves limiting technology, especially during the evening hours. Shut off all screens and try to reduce your exposure to light for at least one hour before bed to reduce any potential disruptions to sleep patterns.2
Finally, ensure you have a dark, cool, and comfortable sleep space combined with a consistent bedtime to help round out your day.
Things to consider with the circadian diet
Initially, people may experience hunger during the fasting period of the circadian diet, especially those who struggle with nighttime eating or blood sugar control. These issues generally can be avoided if the fasting period is introduced slowly over a period of time, with gradual increases to the fasting window.
Many people have predetermined thoughts about food and it can be helpful to clean that slate and unlearn what you think you know about food. For example, avoid categorizing food as “good” vs. “bad” or even “breakfast” vs. “supper” foods. Aim to become more adventurous in the kitchen – this could mean eating chicken and salad for breakfast or a hearty bowl of lentil soup.
Following a circadian diet means listening to your body and its needs. This can be a challenge if you struggle with unhealthy food cravings or are new to a whole foods way of eating. Ask for help and take it slow. If you have a significant medical concern or if you’re unsure where to start, consider speaking with a knowledgeable healthcare provider who can help support you with a personalized plan.
Every step, even if it seems small, counts. The key is what you choose to do every day. Daily habits and routines have the most significant impact on circadian rhythm and offer an opportunity for anyone to optimize circadian health, contributing to better overall health and wellness.
1. Zheng D et al. Trends Immunol. 2020;41(6):512-530.
2. Aulsebrook AE et al. J Exp Zool A Ecol Integr Physiol. 2018;329(8-9):409-418.
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