Most replayed moment: How to stop fighting your body clock | Prof. Debra Skene

Biological rhythms and health

0:00Hello, 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.

0:10Every 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.

0:45One 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 to 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

1:16based 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

1:48clocks, et cetera, 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.

2:20If 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 is not that I might be awake during the night and not seeing as much sunlight. It's the fact that my body clock is out of line with how I'm living. You know, if I was going to live in a cave for a month, like I'm not having the same risk

2:50as 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

3:25the time is. We've got our body clocks. But anyway, that social clock is telling 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.

3:59And 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've been 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

Meal timing and glucose rhythms

4:37health 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.

5:13So 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,

5:43like 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. It doesn't shift the melatonin rhythm, for example. Whereas light shifts the melatonin rhythm, the food only shifts the glucose rhythm.

6:18So you're saying that if I regularly eat on a different pattern, 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. Somehow you're on a schedule where that is normal for you. Whereas if I eat at midnight, 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.

6:52So 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 the food irregularity. I mean, I definitely know there are researchers at King's that study this and others.

7:28So 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 in 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.

7:59Exactly. 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.

Daylight saving time impacts

8:12I 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. And it like 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 a hundred years ago now. Is it a good idea? We believe being on what we would call standard time,

8:45which 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,

9:16there'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?

9:46It'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 has got to be worse for our health. That's where we are.

10:18Now we just have to prove it.

10:23That's it for this week's recap. If you're listening to this, you're already on your way to living healthier through better nutrition. And at Zoe, we're doing everything we can to help you on your way. So we've developed Daily 30, a delicious dietary supplement to add to your meals. Because we're Zoe, we ran a clinical trial testing Daily 30. The results were staggering. It's selling out in the UK and we're working hard to bring it to the US as soon as possible. Sign up to the waitlist at zoe.com slash daily30.

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