The relationship between nutrition and sleep has been studied time and time again. However, there are some basic principles that most nutritionists will agree on when it comes to which foods and drinks affect your sleep negatively.

In this Sleep Matters podcast episode, Dr Pixie McKenna chats to award-winning nutritional therapist Christine Bailey and expert in nutritional medicine, Alan Flanagan. They discuss how nutrition can help or hinder a good night’s sleep and what you can do to ensure your diet doesn’t ruin your slumber.

What’s discussed in this sleep and nutrition podcast:

  • What affects circadian rhythms
  • Eating late at night
  • Eating schedules
  • Hydration
  • Caffeine
  • Supplements
  • Drinking alcohol before bed
  • Lack of sleep’s effect on hunger
  • Best practices and tips

Useful related articles:

Dr Pixie McKenna [00:00:07] Hello everyone and welcome to the Sleep Matters podcast from Dreams. Everything you need to know about how to get a great night’s sleep and why it matters so much. I’m Dr Pixie McKenna. And in this episode, we’re chatting about how important what we eat is in terms of getting some good sleep, and also we’re dispelling some myths with food and bedtime. So we’re really pleased to say today I’m joined by Christine Bailey and Christine is an award-winning nutritional therapist with over 18 years of experience. She’s also written a number of cookbooks so welcome Christine.

Christine Bailey [00:00:41] Thank you.

Dr Pixie McKenna [00:00:42] And we also have Alan Flanagan. And Alan specialises in communicating nutritional science, and he’s also an expert in nutritional medicine, so hopefully, between the two of them we can dispel some myths, and we can get some tips surrounding food and sleep. Before we get started, how did you sleep last night?

Christine Bailey [00:01:02] Actually, I sleep pretty well and I have to say I’ve got three children and they are all teenagers now, so it’s a lot, lot easier, but my sleep is pretty good. I am a very early riser just because I do a lot of gym workouts. So I’ve now adjusted my sleep patterns so that I go to bed earlier and get up quite early.

Dr Pixie McKenna [00:01:24] What time is bed earlier?

Christine Bailey [00:01:25] For me, around 21:30- 22:00, but then I’m getting up at 05:00-05:30.

Dr Pixie McKenna [00:01:30] Okay that’s all right. I thought you were going to say 20:00 or something. And Alan, how did you sleep last night?

Alan Flanagan [00:01:37] I slept well. Yeah, I think I originally started to become interested in sleep and nutrition for sleep because historically I’ve not been a great sleeper so I was one of those people who tried to troubleshoot as many variables as I could. So I sleep well now, but I do a lot of things to get a good night’s sleep.

Dr Pixie McKenna [00:02:05] OK. So it’s not by accident then.

Alan Flanagan [00:02:07] No.

Dr Pixie McKenna [00:02:07] So for you I mean how has nutrition impacted your sleep or changing your nutrition impacted your sleep?

Alan Flanagan [00:02:14] I think it’s more a question of how we look at sleep in the overall picture of a 24-hour cycle of our day. So we have internal rhythms known as circadian rhythms which govern a lot of our processes. They govern the fact that you would naturally wake up in the morning time, perhaps naturally get sleepy early in the evening, and they govern a whole host of other processes in the body that very much have to do with how we digest, process and use the nutrients in the food we eat. And a big shift that’s occurred in our environment over the last 40 years has been things like artificial light exposure at night, extended evening illumination. People are simply up later. There’s an increased propensity to eat later, and we have a lot of interesting observations and some controlled research supporting the idea that later timing of food intake is not ideal for long term health. And so I think when we’re talking about nutrition strategies to enhance sleep probably the first point of consideration is the timing of our food intake during the day, and not just immediately before bed but actually over the course of the whole day and how that influences our rhythms in a 24-hour sense.

Dr Pixie McKenna [00:03:35] Would you agree with that?

Christine Bailey [00:03:36] Oh absolutely I mean one interesting thing when I see a lot of clients in clinic, one of the first things we will look at is when they eat, how regularly they eat, do they erratically eat. Did they skip meals and particularly the late night eating? I mean that’s a really tricky one for a lot of people. I’ve got quite a few people that have a lot of digestive issues. The last thing you want to be doing is eating a heavy meal late at night particularly if you suffer with heartburn, you’re having any soreness of the oesophagus or bloating, and then you’re eating a meal at nine o’clock at night. It’s really going to keep you up, particularly if you have something that’s quite high fat. What fat does is it’s a lot harder for the body to digest it takes a lot longer and it can also increase stomach acid, so you’re one of these people that already have an oesophagus soreness or heartburn if you then have quite a heavy, fatty meal that is likely to keep you up. So absolutely timing is very important.

Dr Pixie McKenna [00:04:35] So what’s the time period in terms of having your supper or your dinner and then going to bed. How long should you leave it?

Christine Bailey [00:04:44] So for a lot of my clients I encourage them to do what’s called time-restricted eating so let’s try and get them to eat as early as possible but say by about 7:00 so then you’re allowing at least, probably for a lot of clients, three to four hours without having lots of food sitting in your stomach. Some of my clients find that if they eat too early than they might have a snack which will only be a handful of nuts, not a big snack, about an hour or two hours before they go to bed just to stabilise their blood sugar. But that seems to be a really good opportunity for people to get a good meal, but allow time for the digestive system to work before they go to bed.

Dr Pixie McKenna [00:05:27] And as a previously poor sleeper you mentioned, was that something for you?

Alan Flanagan [00:05:35] I found that yes. I used to habitually eat quite late, and I did find that I would have difficulty falling asleep and so the period between going to bed and you actually falling asleep is known as your sleep onset latency, and actually, when you look at the research, it was pretty obvious why I was having that issue. In that meal composition and certainly the timing of a meal in close proximity to bedtime can often increase the time it takes people to get to sleep and then potentially the composition of the meal, and, you touched on it there Christine, but there is some interesting research that suggests if you have quite a high-fat meal before you go to bed it will prevent you having the same amount of time in deep REM sleep that we would want to get that very restful restorative sleep phase. So even though people might have the same sleep duration, their sleep quality may be somewhat impaired, and they don’t necessarily get that quality time spent in REM sleep. So I have found that bringing forward the timing of dinner has helped. The other thing that I think is worth noting is that it’s not necessarily just the timing of dinner, but it’s also the main meal of the day and a kind of energy sense. So I think it is important to qualify that you can still have dinner. I mean it’s not always feasible for people to eat by 7:00 so if people start making hard and fast rules so sometimes I’ll say look it’s fine if you’re home later than that and you have to maybe eat at 8. But what I’d say to someone in that circumstance is have more of your daily energy earlier in the day and then just have a lighter dinner if you are with your schedule and whatever, finding yourself home a bit later than that.

Dr Pixie McKenna [00:07:28] OK. And what about sugar. The big bad thing. SUGAR.

Christine Bailey [00:07:32] Well again, this is all to do with the timing. So if you are someone who is literally going from one meal to another craving lots of sugary foods as a pick me up, an energy source or whatever, then we know that not only does sleep affect blood sugar levels but blood sugar levels can then affect sleep. And if you’re someone where your energy is going up and down your blood sugars going up and down then you can potentially then affect other hormones, such as cortisol and so on that can then also interfere with the production of melatonin. So, you know, you can have people that will eat a lot of sugary refined foods during the day and then find that actually they’re waking up a lot in the night, their blood sugar is all over the place. So there’s nothing wrong with carbohydrates. There’s a big difference between sugar and carbohydrates. And actually I encourage my clients in the evening to have a little bit more carbohydrate, and we know that that can help with tryptophan across the brain which can then help with serotonin and melatonin. So I don’t want people to necessarily go completely low carb particularly not in the evening but the refined sugar that can interfere with sleep patterns.

Dr Pixie McKenna [00:08:47] And would you say that’s an absolute no-no for the entire day or would you say you know what don’t have any snacky bad things from 4 p.m. or 2 p.m. or….

Christine Bailey [00:08:57] I think it’s really the whole circadian rhythm thing is affected by everything you eat.

Dr Pixie McKenna [00:09:03] Right.

Christine Bailey [00:09:03] So just thinking well I’ve been good now, so then I can just gorge on something that’s probably still going to impact the blood glucose. But it’s also a question of can you combine carbohydrates with something else? So if you do want your jacket potatoes or your refined white rice or your white baguette, are you able to include a little bit protein in that to help stabilise the blood glucose? So rather than just gorging on a handful of Haribo or something similar, you know can we get you some carbohydrate that won’t necessarily cause such a big spike, so it’s not all carbs are bad at all, and I think a lot of people get very confused about sugar and carbs. But what we don’t want is very erratic blood sugar throughout the day.

Dr Pixie McKenna [00:09:53] And equally, I suppose we don’t want people to go to bed starving.

Christine Bailey [00:09:56] Well you see this is the thing we talked about not eating too much in the evening but actually if you’re starving, and your blood glucose levels really dip then you’re going to start producing a lot of cortisol and cortisol, which is the stress hormone, will block melatonin. So you need to have something to eat, you don’t want to be starving but equally, don’t want to be over full.

Dr Pixie McKenna [00:10:16] And you get up in the middle of the night and stuff your face and won’t be able to get to sleep.

Alan Flanagan [00:10:19] Well a big part of that is that the primary hunger hormone that we have in the gut that signals hunger to the brain, the peak of that in a circadian rhythm sense interestingly is in the biological evening it’s about 7 p.m. clock time. And so what you tend to see with patterns of somewhat more disordered eating is when people try and restrict energy intake earlier in the day and they end up in the evening then home after a long day, a stressful day maybe, and they haven’t had enough energy intake earlier in the day, they’re quite predisposed to overeating in the evening simply because they’re coinciding coming home having under eaten during the day with that peak in their circadian hunger. So eating more earlier in the day dampens that. That peak in hunger signaling the evening which is why I think for people that are struggling perhaps with that pattern of energy intake and are coming home in the evening and finding themselves overeating, actually taking the time to have a breakfast or consume more energy earlier in the day or have a more substantial lunch can can really help with that overall picture.

Dr Pixie McKenna [00:11:27] And what about hydration. Say being hydrated during the day is that important in terms of facilitating a better night’s sleep?

Christine Bailey [00:11:35] Well it’s interesting because actually, I have quite a few clients that often have to get up in the night to wee, to go to the toilet. So I actually encourage them to drink plenty through the day but then stop about two hours before they go to bed, otherwise, or they may sleep well and in the sense that they get to sleep, but they’re just constantly waking up to go to the toilet. So I think yes hydration of course, and there’s lots of other reasons to keep yourself hydrated but don’t be drinking a lot of liquid late at night.

Dr Pixie McKenna [00:12:09] And where’s your cut off for caffeine?

Christine Bailey [00:12:13] Well that really depends on the individual because you can have what’s called fast metabolisers or slow metabolisers of caffeine. The half-life is anything from three to seven hours they normally say around about five hours. Some people, of course, will say I can drink caffeine until 10:00 at night and I’m fine, but it’s also to do with quality sleep and not just ‘do I actually sleep?’. And so I normally encourage my clients to stop around about three o’clock in the afternoon in terms of caffeine. What they forget is that caffeine is found in a lot of things, not just coffee and tea. And so then if they’re gorging on lots of hot chocolate or chocolate late at night that could equally cause them a few problems as well.

Dr Pixie McKenna [00:12:58] What about you. How do you feel about caffeine?

Alan Flanagan [00:13:00] I think it’s a balancing act between someone’s individual tolerance and I think that generally the 3 o’clock cut off point is sensible for most people. If someone is a slow metaboliser or you know when we say half life we mean that that means that the dose only reduces by 50 percent so someone could still have a lot of circulating caffeine that would impair sleep quality. So for some people, it could just be timing their coffee intake for the morning period before midday. So I think it really does depend and I think people do have to be relatively honest with themselves and their caffeine intake to see are they having the kind of restorative sleep that they should and if they feel that they’re sleeping an eight hour block but still fatigued the next day or perhaps having a couple of wakings in the middle of the night that’s not bathroom related then probably looking at their caffeine intake and seeing, well how late am I consuming caffeine? And could I bring it forward? So I think with things like coffee and tea we have to stack up the quite well-established health benefits of coffee and tea. When I say coffee, I mean black coffee, not a Starbucks venti frappa- something. But we have quite established health benefits to them, so yes they contain caffeine. They also have good health effects. So I think it’s just for the individual – find out where you’re where your cut off point is for yourself. But generally, a kind of two to three p.m. is absolutely sensible.

Dr Pixie McKenna [00:14:29] I have probably about, this is embarrassing to say, I probably have 25 cups of tea a day I drink a serious amount of tea, and I always have done since I was very very young and I sleep like a log. But what you’re saying is I mightn’t really be sleeping like a log. I might I could probably even sleep better if I ditched the caff.

Alan Flanagan [00:14:52] Well you could, unless we lock you in a lab.

Dr Pixie McKenna [00:14:55] No thanks, I’ve done all of that.

Alan Flanagan [00:14:55] And hook up electrodes to your head. It’s really difficult to know what the quality of your sleep is like. I mean I think an easy enough question to ask people is do they have dreams and do they remember dreams. Because typically dream state will occur when we’re in REM sleep. You know you’ll often ask a question, and they’re like I can’t remember the last time I had a dream, so I think it depends. Tea also doesn’t have as high caffeine content as coffee – 25 cups might add up. But I think generally, this particular issue, is very individual and it’s difficult to give any kind of broad black and white recommendations.

Christine Bailey [00:15:37] I often also, when my clients love their tea. What I will do is gradually switch them on to, particularly in the evening if they’re having problems sleeping things like chamomile which we know from the studies have actually been shown to help improve sleep. So it’s not the only one. Obviously there’s lemon balm there’s passion flower, there are lots of these herbal teas, but it is a start. But the other one is rooibos of course which is South African, very high in antioxidants but won’t contain caffeine and a lot of people find that very tolerable because some people will admit to that, so it almost looks like regular tea.

Alan Flanagan [00:16:16] It seems to be the one that’s closest to black tea terms of a substitute that’s caffeine free.

Dr Pixie McKenna [00:16:23] And what about supplements, supplementing your diet. Where’s that going to help me in terms of sleeping?

Christine Bailey [00:16:29] Well, I think the first thing is to get your diet right. And to me, food always comes first. There’s no point if someone’s just having a very erratic fast food refined diet then to just down a load of supplements and expect them to sleep.

Dr Pixie McKenna [00:16:41] That is the sort of modern way of thinking, isn’t it?

Christine Bailey [00:16:43] I’m afraid it is.

Dr Pixie McKenna [00:16:46] I’ll go to the gym, I’ll eat really badly and stuff your face with supplements, and I should be fine. If someone who’s eating a very healthy diet or what appears to be a healthy diet are there any particular supplements?

Christine Bailey [00:16:58] There are certain foods that I would probably get them to start with first. So if we know that things like magnesium can be very useful then I would encourage them to, particularly in the evening, to eat more magnesium-rich foods. Things like, you know, just a handful of almonds or a whole load of leafy greens for example. Equally, and there have been some studies on cherry active or similar sort of tart cherry juice which is a natural source of melatonin. And there have been various studies where just drinking a glass of that about an hour before you go to bed can improve sleep. So there are foods that I would rather they tried first. But yes, there are supplements but equally with magnesium, and if you exercise a lot, because magnesium is an electrolyte we can sweat it out, and a lot of my athletes are often low in magnesium. What they will do is they will have a bath in Epsom Salts which is just magnesium sulfate, and you can get that from any chemist. Simply just soaking in a bath, one it’s relaxing anyway, so there are lots of therapeutic benefits of just calming the body down. But equally soaking and getting a little bit extra magnesium, they’re more natural ways.

Dr Pixie McKenna [00:18:12] What do you think the biggest myths around sleep and nutrition that links what you know people that come in or ask you questions, what’s the crazy stuff that people think?

Alan Flanagan [00:18:23] Well there was there was one study of a milk formula in the 1970s that took a while to be dispelled out of people’s minds. Which is this idea that you know milk has some kind of particular properties that enhance sleep. And actually, there was an article recently in the paper about farmers that were feeding their cows kind of melatonin and saying that they were producing this melatonin enriched milk and that that would enhance lives. So no, I mean typically you know there’s been some kind of myths about, not necessarily isolated nutrients but more things like ‘oh we don’t need to worry about the timing of food intake you know late night eating doesn’t….’ You know. And typically what’s looked at in that sense is weight loss studies where people are eating you know 500/ 700 calories less than they ordinarily would. So in that context of an energy deficit, maybe the timing’s less relevant, but that’s not representative of people at the population. So I think that for me the biggest myth has been that timing is irrelevant for sleep quality and that’s categorically not supported by really any literature outside of the odd weight loss study.

Christine Bailey [00:19:42] For me it’s alcohol because I always get clients who say I have to have a drink that will help me get to sleep and actually it’s unlikely to help. In fact, it’s more likely to cause real problems. We know it can affect things like dopamine which can then be more stimulating so it actually can make you feel slightly more awake it can also interfere with blood sugar, it can also interfere with the circadian rhythm of melatonin production. So although some people will feel that it helps to get them to sleep quicker the quality of sleep is absolutely disrupted and that I think that comes up all the time about oh no I haven’t nightcap. Probably not a good idea.

Dr Pixie McKenna [00:20:28] And I guess the quality of sleep after if people have had a really sociable weekend and they’re heading into Monday the quality of their sleep on a Sunday night isn’t going to be great is it?

Christine Bailey [00:20:38] Well and the other interesting thing is that can then set off a really bad pattern for the whole week because lack of sleep can also interfere with the hunger hormones as well. So it can actually depress hormones like leptin which are related to appetite but actually increase your hunger and then what you’re more likely to then do is start craving on things to keep your energy up so the sugar the caffeine and then, of course, that will have a knock on effect the next day. So it can be a little bit of a vicious cycle. Yeah and particularly if you’ve had a great party weekend.

Dr Pixie McKenna [00:21:12] Yeah, yeah.

Alan Flanagan [00:21:13] And when you look at that research people assume that it is dramatic sleep deprivation. It’s really not. A lot of that research that looks at the effects of lack of sleep on subsequent energy intake, for example, and appetite and hunger. You’re talking five and a half hours sleep. Some people would consider that a good night’s sleep. And what we see predictably the next day is a preference for very energy-dense foods that are high in sugar fat and salt, and that’s often because there is a desire to have increased energy for the extended wakefulness of having a lack of sleep. And there’s up to a 22 percent increase in people’s caloric intake the following day after five and a half hours sleep. That ties to the dis-regulation of appetite and hunger hormones. So there is a knock on effect, and the other thing that’s come out of that research is we’ve typically associated jet lag as quite extreme. You know you fly to L.A., and you’re out of kilter, but there’s a term now coming out of the circadian research called social jetlag. And that’s basically what it sounds like, it’s people spend their Monday to Friday trying to catch up on the sleep they lost from the weekend, but then they get to Friday.

Dr Pixie McKenna [00:22:23] I have that the opposite way round!

Alan Flanagan [00:22:25] You’re trying to make up for the week’s work at the weekend. But yes that social jetlag is the difference between how much sleep you would need and how much you actually get relative to not just socialising but also work and stuff. So it is something for us to generally start paying attention to. You know how much do we knock ourselves out of kilter a little bit. Not necessarily in the extreme sense like flying to Australia but actually kind of habitually in our daily or weekly lives.

Dr Pixie McKenna [00:22:53] And so what would your simple changes be to someone who’s thinking right what do I need to do nutritionally. I’ve looked at everything else. I can’t sleep I got a blackout blinds the earplugs the good bed etc. I still can’t sleep.

Christine Bailey [00:23:06] So firstly going back to the sort of timing. So three regular meals, evening meal try and bring it slightly earlier if they were someone that was eating late. Make sure you’ve got some easy to digest protein and carbohydrates so you know nothing complicated it could just be rice with some fish and vegetables. I mean it’s nothing complicated. Not lots of spice if you get lots of heartburn not lots of fat if you get heartburn or digestive problems. And you know if you are struggling then maybe a glass of cherry juice an hour before you go to bed, a handful of nuts, an Epsom Salt bath. Those sort of simple changes can have actually quite a profound effect on the quality of sleep.

Dr Pixie McKenna [00:23:51] Any other tips from you?

Alan Flanagan [00:23:53] I would say, and we briefly touched on this earlier but in the overall circadian kind of rhythm over the whole day giving yourself distinct cycles of feeding and fasting that correspond with being awake or being asleep. So a simple thing for people is just having an eating window of around 10 maybe 11 hours. What you see at the population level in the UK as most people are spending up to 15 or 16 hours a day you know in a post fed state. So you know if you’re having breakfast at 8:00 having dinner at 7:00. But again if you’re not going to be able to have dinner that early you could delay breakfast an extra hour, for example, and eat at 8:00, and generally in that sense what I’d say is having more of your energy intake early in the day in between your breakfast and your lunch have to have more most of your daily energy and dinner then relatively lighter compared to breakfast and lunch. And in terms of composition of the meal, I would agree that generally a good quality carbohydrate and protein-based meal with a slightly lower fat content.

Christine Bailey [00:24:56] For some of my clients as well interestingly there’s now quite a lot of research on the gut and how that can affect and neurotransmitter production and your sleep patterns. And so for some of them, I will encourage them to have what we call fermented foods during the day as well. So things like yoghurt, kefir, sauerkraut. Because there’s now a lot of good research on making sure you’ve got a good microbiome diversity which then also affects the brain but also produce things like serotonin and so on. So if someone comes to me with some digestive problems, then I would absolutely be looking at that to help them sleep.

Dr Pixie McKenna [00:25:38] So we’ve definitely got to look beyond the blinds and the bed and its basics as you said to people who are sitting there with their big plasma’s and stuffing their faces with their supplements and actually they’re eating terribly badly which is why they don’t sleep. And so. So your take-home message. The one thing you would do if you were somebody who’s listening to this and they haven’t thought about diet, what’s the one key thing?

Christine Bailey [00:26:02] Bring the evening meal slightly earlier. Don’t eat very late at night.

Dr Pixie McKenna [00:26:06] Okay.

Alan Flanagan [00:26:08] Yeah and give yourself distinct cycles of feeding and fasting.

Dr Pixie McKenna [00:26:12] Sounds like a cat.

Alan Flanagan [00:26:14] Yeah. It really does. But yeah I mean when we’re asleep that night period it’s supposed to be a fasting phase and the wakeful period is when we consume food. People are often not eating until 13:00 and then having dinner as late as 22:00 and I would say be mindful of that window. Bring it slightly earlier and try and maybe to keep things to a 10 and 11-hour daily window.

Dr Pixie McKenna [00:26:36] So do you reckon you’re going to sleep well tonight?

Christine Bailey [00:26:37] Oh, yes, absolutely.

Dr Pixie McKenna [00:26:39] Yeah.

Christine Bailey [00:26:40] A little bit of cherry juice before I go to bed. I’ll be fine.

Dr Pixie McKenna [00:26:43] Cherry juice. What’s your secret weapon?

Alan Flanagan [00:26:45] Well my secret weapon has typically been the light exposure thing to be perfectly honest. But it’s Thursday, and I plan on having a glass of wine, so I’ll take the consequences.

Dr Pixie McKenna [00:26:57] Guess they’re not heeding your own advice then Alan.

Alan Flanagan [00:27:03] I’ll take the consequences.

Dr Pixie McKenna [00:27:03] Have a cherry juice tomorrow; you’ll be fine. Thank you so much. Alan and Christine lots of tips I think for people who maybe haven’t thought about diet. So really really good. Thank you.

Christine Bailey [00:27:13] Thank you.

Alan Flanagan [00:27:13] Thank you.

Dr Pixie McKenna [00:27:14] That’s all from this episode of Sleep Matters from Dreams. If you want to hear more, go to Dreams.co.uk, YouTube or any of your usual podcast places. And if you enjoyed this podcast, we’d love it if you could subscribe and leave us a review.

Watch the full Sleep Matters podcast playlist on YouTube.