Updated: Apr 12, 2024Veronika Larisova
What is circadian eating?
Circadian eating is a type of intermittent fasting or time-restricted eating that aligns one's eating patterns with the circadian rhythm, the natural 24-hour cycle that regulates many physiological processes, including metabolism, hormone production, and sleep-wake cycles.Find out the difference between intermittent fasting, time-restricted eating and circadian eating in our previous blog ‘Intermittent Fasting v Time-restricted Eating v Circadian Eating, what's the difference?’
We have an internal body clock that decides when we get hungry and how our body uses energy. This clock is in our genes and every cell in our body. It regulates our immune and brain function, metabolism, detoxification, and repair. Watch a Ted Talk by Satchin Panda, the fasting guru, to learn how it works.
When the circadian clock doesn't match your daily habits, you might start experiencing metabolic issues, like trouble with your blood sugar and weight gain. This kind of mix-up, called circadian misalignment, hits night shift workers the hardest because they're awake at night, sleep during the day, and often eat when most people are sleeping. But it's more than just a problem for them. You could be facing something similar called social and eating jetlag. That's when you stay up late, wake up late, and your meals drift later into the evening. This can sneakily lead you to eat more and pack on extra pounds. Furthermore, even just moving the eating window to a couple of hours earlier or later in the day will give you jet lag symptoms, and it takes about two days to recover from it. Trying to sync your mealtimes with when your body naturally wants to eat might help you avoid these issues. Eating a smaller dinner earlier and sticking to the same mealtimes throughout the week and weekend could lighten the load on your heart, keep your weight in check, improve sleep, enhance physical and cognitive performance, and boost other aspects of your health.
When you eat is as important as what you eat:
In the morning
Your melatonin levels are high, and eating at this time can inhibit a proper glucose response to food.You should wait to eat or drink anything other than water for at least one hour after waking. Sticking to water is the best strategy instead of using a blood glucose monitor because anything containing sugar (even just 1g) will break the fast.
Eat protein at breakfast. Research shows that muscle protein synthesis is more efficient in the morning and that eating protein at breakfast leads to greater muscle hypertrophy. You can add our Collagen Protein Bar to a smoothie or crumble it over yoghurt for a quick extra protein.
In the evening
There are many reasons why dinner should be your smallest meal eaten at least 2-3 hours before bedtime.
First, eating a heavy meal too close to bedtime disrupts your sleep. Digesting food creates heat (the thermogenic effect of food) and increases your core temperature, thus affecting your sleep. We get the best sleep when our core temperature is lower.
Secondly, not eating doesn’t equal fasting. If your gut is full of heavy food when trying to sleep, you compromise many physiological processes crucial for health, recovery, and anti-aging. For example, you can hinder the production of NAD+, which is necessary for DNA repair, anti-aging, gene expression, and the function of immune cells.
Getting to the fasted state takes time and depends on many factors, such as the macro-nutrient composition of the last meal you had, the volume of the meal, when you ate it within your circadian rhythm, and what you did before and after the meal. Eating a small meal 2-3 hours before bedtime, followed by a 30-minute walk, will help you to get to the fasted state by the time you sleep and allow you to maximise the health benefits of the fast.
Sleep-related fasting is especially important for health reasons, including gut and metabolic health, autophagy and resetting the circadian clock. Sleeping in a fasted state also allows the glymphatic system to clear out any waste in your brain. There’s also evidence that sticking to this eating regularly will lead to enhanced fat burning while in caloric restriction.
How to get to the fasted state quicker in the evening
- Eat a small, easily digestible meal low in starchy carbohydrates and fat and high in protein at least 2-3 hours before bedtime.
- Walk or move after dinner for at least 20-30 minutes.
Chief circadian eating guidelines:
Breakfast like a king, lunch like a prince, dinner like a pauper!
- Wait at least one hour after waking before you eat or drink anything other than water.
- Eat breakfast by 10 a.m. to benefit from enhanced protein synthesis and glucose control. This is the time to have more protein and carbohydrates.
- Eat breakfast at the same time every day to synchronise your circadian clock.
- Consume enough salt to prevent hunger and shakiness when fasting.
- Have dinner at least 2- 3 hours before bedtime. It should consist of protein and non-starchy vegetables in small amounts.
- Walk for 30 minutes after dinner to clear out glucose, speed up gastric emptying, and reach the fasted state quicker.
- Stick to the 8-10-hour eating window.
- Follow the same pattern on the weekend to prevent a ‘social and eating jetlag’.
- Use My Circadian Clock to learn more, stay on top of it and keep motivated.
Chief Beef Bars and Chief Biltong are perfect for evening snacks or to use in evening meals, as they are easily digestible, low in carbohydrates and fats and high in protein.
Veronika Larisova
Co-Founder, Registered Nutritionist, Exercise Physiologist
References:
- Circadian rhythms and meal timing: impact on energy balance and body weight
- My Circadian Clock: Science
- Time-restricted Eating for the Prevention and Management of Metabolic Diseases
- Distribution of dietary protein intake in daily meals influences skeletal muscle hypertrophy via the muscle clock
- Intermittent fasting promotes type 3 innate lymphoid cells secreting IL-22 contributing to the beigeing of white adipose tissue
