Sleep: Chrononutrition- Seasonal Eating

Timing is everything. In this blog, we will explain the best times to eat for circadian rhythm, optimal sleep and optimal health. We will look at seasonal eating and how it supports a healthy circadian rhythm. Read on for the details and how you can get better sleep by paying more attention to your diet! 

In this blog, you will learn:

• What is chrono nutrition 
• When is the best time to eat to support circadian rhythms and optimize sleep
• How seasonal local eating can support circadian rhythms and optimize sleep

WHAT IS CHRONO NUTRITION?

Circadian clocks manage many cycles in the body from when we sleep and eat, to cellular rhythms in gene expression and energy metabolism. The body’s circadian clocks are very sensitive to nutrient and hormone signals, which are influenced by the food we eat (Flanagan A, 2020). 

Chrono nutrition looks at the interaction of the body’s circadian rhythms, nutrition and timing of eating. The foods eaten, nutrient content, the size and timing of a meal all affect circadian rhythms and can modulate cellular circadian clock systems throughout the body (Arola-Arnal A, 2019). The relationship is two-way. Circadian rhythms influence digestion, hunger and metabolism while eating, meal timing and nutrition content is one key way to train the circadian rhythm. 

Chrono nutrition is how the body responds to food at different times of the day, fasting and the effect of a consistent meal schedule. It influences health and metabolic issues like overweight/obesity, high cholesterol, type 2 diabetes, high blood pressure and more. Eating at a time that interferes with circadian rhythms can disrupt these rhythms in peripheral clock tissues, such as the liver. This can disturb metabolic processes, blood sugar management and digestion.

In today’s world, what and when we eat has changed substantially. There is always high calorie food available. People often eat late at night or even in the middle of the night. These newer, more disordered eating habits and patterns disrupt and dysregulate the timing of circadian systems in the body (Flanagan A, 2020). This can have huge impacts on sleep and metabolic health (Flanagan A, 2020).

WHEN IS THE BEST TIME TO EAT?

Timing is everything, especially when it comes to eating and the body’s circadian rhythms. For optimal circadian rhythm, sleep and health, the best times to eat are: 

• Eat most calories in the early part of the day when the circadian rhythm is most active.
• Eat within a consistent daily window of 12 hours or less per day to optimize digestion and circadian rhythm.
• Avoid large meals close to bedtime, during the night or even very early morning when the body may not digest and process meals efficiently.

Daytime Eating

Eating during the morning and afternoon is ideal, when the circadian rhythm is most active. This prepares the body to be most efficient at digesting, absorbing and metabolizing food (Manoogian E, 2019). 

Insulin sensitivity is greater in the morning. Insulin is needed to regulate blood sugar which increases when we eat. This optimizes blood sugar regulation as larger meals are processed better when eaten in the first half of the day. 

Evening Eating

Eating late at night is associated with changes in body fat, weight gain, poor ability to digest sugar, high cholesterol, higher levels of fat in the blood and is a risk factor for chronic disease (Manoogian E, 2019). A late dinner can disturb sleep via possible acid reflux, heartburn, indigestion/ poor digestion or blood sugar imbalances. Eating late is associated with a higher BMI and less sleep (Binks H, 2020). 

Melatonin regulates circadian rhythm and sleep wake cycles and is released as darkness falls. As the body releases melatonin, it releases less insulin, which inhibits the ability to digest glucose. Eating a meal too closely to the time of melatonin release, late in the evening, means glucose won’t be handled properly and digestion may be off (Manoogian E, 2019). 

It is best to finish eating 2-4 hours before going to sleep (Binks H, 2020).  

Eating too early in the evening won’t help with sleep though. Going to bed hungry can lead to drops in blood sugar during the night. This will trigger a cortisol release to raise blood sugar which increases alertness and possible waking up in the middle of the night. 

Meal Schedule

Meals help to regulate the circadian rhythm and optimize the sleep wake cycle (Schuppelius B, 2021). A consistent daily meal schedule helps with weight loss, can increase energy, improve sleep and overall quality of life and reduce metabolic risk factors for chronic disease (Manoogian E, 2019). Having dinner at roughly the same time every night supports the circadian rhythm. The body can prepare for a meal and know when to produce digestive enzymes for optimal digestion. 

Eating at the exact same time every day may not always be doable. It may take some trial and error to discover the best mealtimes for you, your body and your work/family/social schedule. 

Eating Windows

Eating over a longer time window and/or frequently changing that window is linked to worse sleep and overall health. In one study, people who ate during a 10-hour eating window with a 14 hour daily fast had significant weight loss and improved fasting blood glucose levels (Peeke PM, 2021). This type of eating supports the circadian rhythm. It gets the body into a routine, makes it easier to fall asleep and wake up at the same time every day and improves sleep quality (Peeke PM, 2021).

Time Restricted Eating (TRE)

TRE is eating and drinking all of your daily calories within a consistent 8 to 12-hour, or shorter, daily window. It is a type of intermittent fasting. Time Restricted Eating has positive metabolic effects. It can promote weight and fat loss, decrease cholesterol/ blood pressure/ BMI and waist circumference. TRE improves glucose tolerance and decreases insulin and triglycerides (Adafer R, 2020). 

Limiting the timing of food consumption as in TRE resets and aligns the circadian clock (Adafer R, 2020).

• In animal studies TRE helps to prevent and reverse obesity and Type 2 diabetes, supports good gut bacteria and reduce inflammation (Manoogian E, 2019). 
• In studies in humans, TRE of a 4 up to 11 hour daily eating window decreases blood pressure, improves insulin and blood sugar, cholesterol and blood pressure (Adafer R, 2020). It can improve weight, energy levels, sleep and appetite (Manoogian E, 2019). 
• Calorie reduction happens naturally in a limited time window (Manoogian E, 2019). TRE helps to reduce grazing and snacking, which can increase calorie intake, negatively impact sleep timing and quality/ blood sugar/ digestion and ultimately metabolism (Peeke PM, 2021).

A shorter eating window is healthier. Some people eat during 10 hours/ fast for 14. If you find a short window is difficult to do based on work, family and other obligations, then at least consistently stick to a 12-hour window of eating/ 12 fasting. An eating window of 12 hours or less per day can help maintain high quality sleep (Schuppelius B, 2021). 

What about a Bedtime Snack?

It depends. Ideally, dinner is completed 2-4 hours before dinner. But if you do end up feeling a little hungry before bedtime, eating something small can stabilize blood sugar levels and help to fall asleep faster. The risk of eating before bed is having acid reflux, heartburn, digestive issues, weight gain and poor sleep. Don’t make it a nightly habit, but if it is necessary because you are out of your normal routine, then choose the right snack options. Foods low in added sugar and high in fiber, with tryptophan and melatonin, can trigger sleepiness.  Fruit like cherries and kiwis, nuts /nut butter are all healthy options that won’t slow down digestion or spike blood sugar in the middle of the night.