Chrononutrition Explained
When you eat is as important as what you eat.
It’s all about timing (chrono)…
Ever since I started PTing, one of my big messages to clients to is to eat more earlier.
In fact, if you’d like chocolate cake,
have it for breakfast.
(You’re more likely to burn it off that way).
In addition, new research into our circadian rhythms shows that food is metabolised differently at different times of the day. “Circadian rhythm, also known as the body's internal clock, is a natural, roughly 24-hour cycle that dictates when you are most alert and when you are ready for sleep, influencing various physiological processes.” It’s interesting to consider your internal clock when it comes to nutrition, rest and recovery.
If you’re hankering for late-night cookies, just imagine slapping them onto your thighs. That’s right, calories consumed at night (that tend to be of the junk food variety) are more likely to be stored as body fat. After all, all you’ll be doing is going to bed after… Save that treat, and enjoy it in the morning, when you’re body is primed for action and needs the fuel for energy. This is especially important if you’re trying to incorporate more exercise into your life. Be sure to eat enough during the day.
A good rule of thumb is to eat between 8 and 8, that’s 8am and 8pm. So your body theoretically has 12 hours downtime to rest, repair and restore energy.
I have found great client success with this simple concept. It means you can eat pretty much what you want, as long as you’re mindful to “breakfast like a king / queen, lunch like a prince / princess, dinner like a pauper”.
That simply means your evening meal is not the largest of the day.
Ideally eat half of your calories by the end of lunch.
Enjoy a morning snack (something more than a coffee and a biscuit!) to keep your blood sugar levels stabilised, especially important if you have a busy day or demanding job. Even if you simply work at a desk, your brain still uses 20% of your energy, so stable blood sugars and feeding your body during the day will aid concentration, memory and problem solving.
I find putting healthy snacks somewhere obvious helps. Put easy-to-eat food on your desk or in your work bag. Even if you WFH, place planned morning snacks on your kitchen counter where you’ll see them before scouring the fridge. My back bench in the studio is often littered with snacks including fruit, oatcakes, dates, nuts and seeds.
The research into circadian rhythms and how different systems in the body are affected at different times of day is very new. Previously it’s not been possible for the fluctuations of hormone levels in the blood to be monitored over time with accuracy. ‘The Inner Clock: Living in Synch with our Circadian Rhythms’ is an excellent, easy-to-read place to start research, published late 2024. A more in-depth study is by Russell Foster, Professor of Circadian Neuroscience, University of Oxford was published in 2022, ‘Life Time: The New Science of the Body Clock, and how it can Revolutionize your Sleep and Health’ is a hefty book, but has a whole chapter on the subject of Chrononutrition.
Quoting from page 273:
“By gaining a better understanding of our metabolism, and how our metablic pathways are regulated by the circadian and sleep systems, we will be better armed to navigate the difficult path between healthy eating and metabolic syndrome… The relationship between the circadian system and metabolism is an emerging area of science, but already it is transforming our understanding…”
I’ve had a Google alert for Chrononutrition and there’s more research being posted online everyday. It’s gone from being a niche field of research, to mainstream science - in fact Nature Journal recently published an article on it…
Conclusion
From Nature Journal, 26 March 2025: “Our findings suggest that eating later and having longer eating window are associated with higher dietary intake and higher BMI.”
