ZOE Science & Nutrition - Most replayed moment: How to stop fighting your body clock | Prof. Debra Skene

Episode Date: October 6, 2026

Every one of us runs on a biological rhythm - a finely tuned system that controls when we feel alert, when we feel tired, and even how we process food. But here’s the problem: modern life doesn’t always respect this rhythm. Late nights, early alarms, and irregular meals put many of us out of sync with our own biology. I’m joined by Professor Debra Skene to explain why this mismatch matters, and how you can transform your health by aligning your lifestyle with your internal ticker. 🌱 Try our science-backed and tasty wholefood supplement Daily30 🌿Let your gut microbes snack on the ZOE Gut Health Bar Get our brand-new app and Gut Health Test designed by world-leading gut health and nutrition scientists to build healthy eating habits 👉 Join ZOE Follow ZOE on Instagram. 📚Books by our ZOE Scientists The Food For Life Cookbook Every Body Should Know This by Dr Federica Amati The Appetite Reset by Dr Federica Amati Food For Life by Prof. Tim Spector Ferment by Prof. Tim Spector Good Mood Food (preorder) by Prof. Tim Spector Free resources from ZOE The Smart Snacking Guide: How to feed your gut, fuel your day, and snack without guilt The Hormone Harmony Guide: Tuning Your Body’s Internal Orchestra   Eating for Better Brain Health: Your brain-gut blueprint How to eat in 2026 - Discover ZOE’s 8 nutrition principles for long-term health Live Healthier: Top 10 Tips From ZOE Science & Nutrition Gut Guide - For a Healthier Microbiome in Weeks  Better Breakfast Guide Have feedback or a topic you'd like us to cover? Let us know here. Episode transcripts are available here.

Hello and welcome to Zoe Recap, where each week we find the best bits from one of our podcast episodes to help you improve your health. Every one of us runs on a biological rhythm, a finely tuned system that controls when we feel alert, when we feel tired, and even how we process food. But here's the problem. Modern life doesn't always respect this rhythm. Late nights, early alarms and irregular meals put many of us out of sync with our own biology. I'm joined by Professor Deborah Skeen to explain why this mismatch matters and how you can transform your health by aligning your lifestyle with your internal ticker. One of the biggest purposes of this biological clock is actually to separate the times when you're eating and the times when you're not so that your body is sort of prepared to deal with the influx

of everything that comes from the food and then have a period when you're not. When you're fasting. And that therefore if you are eating suddenly like in the middle of the night when I'm not expecting, into it. Actually, your body isn't prepared and that has some quite big negative health impacts? Yes. So we think, and then over time, because this, let's say, this increase in fats at night, based on the food you eat, if that accumulates over time, this could be one of the explanations. Once we knew the epidemiology showing this increased risk of these disorders, particularly metabolic disorders, cardiovascular problems and cancer, people,

have, you know, really tried to go, well, what is the contributing factor? And so you get all these diagrams of light at night, eating food at night, mismatch of clocks, etc. So that it all then funnels down into maybe this is increasing the risk. But as I say, the precise mechanisms are not known. And what's the hierarchy of these things? Is it because you've shifted your sleep-wake timing? Is that the thing that's the most disruptive for disease? Or is it the fact that you've shifted your feeding fasting, for example? So we don't know that yet.

If we know that, then we can start giving advice to shift workers and advice to people who employ shift workers. You're saying the thing that is causing most of the problem, It's not that I might be awake during the night and not seen as much sunlight. It's the fact that my body clock is out of line with how I'm living. If I was going to live in a cave for a month, I'm not having the same risk as I am sort of shifting between day and nighttime and my body clock moving around. Living in a cave for a month is pretty healthy because you would be just going to your own time.

So you would then be living according to your body clock timing. And this, in theory, is the most healthy thing to do. The problem we have is that we have a social clock that's set on our wrists here. Chronobiologists don't wear watches because we don't need a social clock to tell us what the time is. We've got our body clocks. But anyway, that social clock is telling us. you, please wake up, please go to work, please go to school. And this can be in conflict with our body clock.

And it is. And this is where we get this thing of the speeds of people's clocks. Now we get clocks that are slow and we get clocks that are fast. And people who have slow clocks are more evening types or owls, you know, late types. and people who have fast clocks are more morning types or what we call locks. And they all have to fit into this sort of nine to five program that we have. And so some people are really living against their biological clock system. You know, if you're a late type and you're being forced to wake up at six o'clock in the morning

to go to work. This is a big jar and a mismatch that does eventually have some health consequences. My next biggest set of questions, which were all around meal timing, and I understand you've recently been studying this. So what is the advice you can give us? Everybody has focused for so long on what you should eat, but it's now about when. and is there a correct or appropriate timing of food? And there are bigger experts than me at this, but we've done some very controlled lab studies where the question has been,

okay, let's shift the whole meal schedule by five hours. So that would be breakfast, lunch and dinner, moved five hours. And then what happens to our body clocks? and food does not affect our master clock in the brain. So we know that now. We were the first to show this. It had been shown in animals, but we were pleased to see this exactly right.

So we suspect that food affects probably all the peripheral clocks involved in metabolism, like the liver clock, the pancreas clock, but it doesn't go to this clock in the hypothalamus. So that makes some sense. We shifted this meal timing by five hours, and we found that glucose, the rhythm of glucose, also shifted by five hours. So it has the ability to shift the rhythm of glucose, but not any hormones that are driven by. It doesn't shift the melatonin rhythm, for example. Where as light shifts the melatonin rhythm, the food only shifts the glucose rhythm.

So you're saying that if I regularly eat on a different path, and my body, my gut, everything will get used to it and sort of digest it easily if I'm doing that all the time. And so it's almost on a separate body clock. I'm thinking about Spain where they all eat at midnight or something. You're on a schedule where that is normal for you, whereas if I eat at midnight, you know, my blood sugar would go through the roof. We believe that our bodies have a memory of the meals we've had before. And so indeed, the healthy thing is to stick with what you do normally. So Spanish people eating late, that's something they're doing all the time.

It's any disruption to that normality that is a disturbance for the clock system. So, Deborah, are you saying that in terms of meal timing and health, consistent timing of meals is important? I think it's going to turn out that it's right, that we should have consistent meals at the same. time and we should reduce this the food irregularity. I mean, I definitely know their researchers, you know, at Kings that study this and others. So it's this food irregularity that we are all beginning to think isn't good for your body. I think you're saying that eating sort of at the same times and the same pattern is probably good for your health.

But I think you're also saying that if during the week you're waking up early, and then having your breakfast at seven, but you're exhausted at the weekend and therefore you're sleeping into nine, you probably don't want to drag yourself out of bed at seven in order to eat your breakfast. Exactly. That's what I'm saying.

So when we say to people, they should have consistent meal timings that shouldn't change, we should see what those are, you know, first. I know you've also expressed opinions around daylight saving time, This time when like twice a year our clocks change by an hour. And I was thinking about this this morning because I know it always creates havoc with my kids and particularly my daughter's sort of sleep pattern. It takes at least a week for her to like get back into the right pattern.

And I understand we did that because we think it's a good idea when we introduce it as governments, you know, probably 100 years ago now. Is it a good idea? We believe being on what we would call standard time, which is the time that we have during the winter months, is the better time for your health. Because in the standard time, our body clocks are more aligned with where the sun actually is. So when we're in the standard time, when we go outside at noon and they're more closer together, when we're in British summertime, there's a bigger gap. So there's more of a mismatch between our body clocks, which is driven by the sun clock, you know, our light dark cycle, all the things we've talked about today, and this man-made social clock.

and any mismatch between our social clock, that clock, and our body clocks, the more unhealthy it is. So how would you study really the effect of, what is it, six months? It's a six-month period. And how do we know how it would be different if we just stayed on standard time? So we can only just use the principles that, you know, we don't want to suggest anything that makes the gap. between living according to the light dark cycle and the sun clock and our body clocks, and anything that makes that gap bigger with the social clock is got to be worse for our health. That's where we are.

Now we just have to prove it.