The sixth variable that I will be manipulating across a two week period to examine its impact on sleep is food. I will be seeing if the type of food that we eat and the timing of our eating can impact our sleep quality.
I will discuss what my data shows, how easy or difficult I found this strategy to implement, and what previous research says. These three factors will be combined for an overall score and grade on how effective manipulating our diet can be at improving our quality of sleep.
The Relationship Between Food and Sleep
Now I am not a dietician, nutritionist, naturopath, medical doctor or personal trainer, so my understanding of how food could help sleep and the brain is not as in depth as other people’s may be.
Food is not something I generally focus on too much in my treatment of insomnia either, but I am aware that being too hungry or too full can both have a detrimental impact on our sleep quality and how quickly it can take to get to sleep.
When breaking it down further to look at the type of food and its relationship with sleep, a brief google search on this topic was fairly confusing.
There are a lot of foods that are meant to have a potential benefit on sleep, including:
- whole grain breads
- crackers and pretzels
- cereals, including oats
- rice (white or jasmine)
- spinach, lettuce or kale
- sweet potato
- nuts, including walnut, pistachios and almonds
- peanut butter
- dairy, including milk, cheese and yoghurt
- cherries, bananas and watery fruits
- seafood, including shrimp, lobster and tuna
The reason given for these benefits include that they are high in tryptophan (which metabolises into melatonin and serotonin), melatonin, magnesium or potassium and therefore help us to feel sleepy or relax our muscles. Watery fruits are the exception to this, and are thought to help us to fight dehydration.
There are also other foods that are meant to have a detrimental effect, including:
- A bacon cheeseburger or greasy, heavy meals
- processed meats
- orange juice
- anything with caffeine, including chocolate
- curries or things with heavy spices
- tomato based foods
- Meals high in protein
The reason given for avoiding these foods include a greater risk for an upset stomach, heartburn, indigestion, elevated arousal levels and too much energy needed to break down these foods in our digestive system.
For the first week, I tried to eat healthily during the day, but then have a dinner or snack before bed that was considered potentially harmful for sleep. This included:
- A burger and chips on the Sunday night
- Orange juice on the Monday night
- Pepperoni and Olive pizza on the Tuesday night
- A creamy tomato pappardelle pasta with chilli on the Wednesday night
- A Thai green curry on the Thursday night
- Honey mustard chicken breast on the Friday night
- A double chocolate sundae from the Lindt cafe on the Saturday night
For the second week, I tried to have as many healthy meals as possible, and had a light snack before bed on the Sunday, Monday and Tuesday night about 30 minutes before bed. This consisted of:
- Cheese and crackers on the Sunday night,
- Peanut butter on toast with honey on the Monday night, and
- Oats with mixed berries and milk on the Tuesday night.
From the Wednesday through to the Sunday I was on a Vipassana silent meditation retreat, and was unable to modify my food intake from what was being served to us. I ate:
- Oats, banana and yoghurt for breakfast at 6:30am every morning,
- A simple vegetarian lunch consisting of vegetables, salad and brown rice at 11am, and
- Two pieces of fruit for dinner at 5pm.
We were not able to eat past 5pm, so it makes for a nice comparison to view the effects of timing of food on sleep plus no processed foods and no meat.
Comparison 1 – Type of food: “bad” for sleep vs “good” for sleep
Subjectively, I woke up less each night with the food that was meant to be bad for my sleep, and also spent much less time awake per night. My sleep efficiency was better after the bad food too, and my sleep quality was rated as exactly the same (4.42/5) in comparison to the week where I ate foods that were meant to be good for my sleep.
It took 1.5 minutes longer to fall asleep after the bad food than the good food, but that is hardly enough of an improvement to focus too much on what I eat before sleep if I am wanting a good night’s sleep in the future.
Comparison 2 – Timing of eating: week 1 vs week 2
Subjectively, by eating earlier in the day and at night it did seem to have an impact on my internal body clock, or circadian rhythm. I was able to get to bed the second week by 10:15pm on average, which is the earliest it has been all year, and I still fell asleep within 8 minutes each night.
By getting to bed earlier, I was able to stretch my time in bed to 8 hours and 16 minutes per night, and obtain 7 hours and 54 minutes of sleep each night, which is also a personal best for me for the year.
My sleep efficiency and sleep quality were both excellent too, so eating earlier in the day does seem to help me to fall asleep earlier and stay asleep longer.
Objectively, the depth of my sleep was better during the first week when I was eating foods that were meant to be bad for sleep than it was during the second week when I ate earlier and less food at night.
Let’s compare Mar 31 (30/3/17 on the sleep diary) to Apr 06 (05/4/17 on the sleep diary data). I obtained more sleep on Apr 06, but it had two visible awakenings during the night, more time awake during the night, and a poorer ratio of restful:light sleep.
This means that objectively my sleep quality was a little worse during the second week – the exact opposite of what I would have expected before conducting this experiment.
IS MANIPULATING YOUR FOOD CONSUMPTION A GOOD SLEEP STRATEGY?
IS IT EFFECTIVE?
Maybe. The type of food didn’t seem to make too much of a difference to my sleep at all, although I may need to change my diet for a lot longer period of time to see the true impact of food on sleep. I also didn’t eat seafood or turkey or elk, so the wonder sleep food may still be out there for those who are willing to give these a go. Eating earlier did seem to help me to get to sleep earlier and sleep longer, but not necessarily better. Based on my data, I give the effectiveness of this strategy a 15/25.
CAN IT BE APPLIED?
Yes. For me, the flexibility of this strategy isn’t too bad, as there are plenty of options that you could still choose from, whether it is for dinner or a pre-bed snack. Eating earlier consistently might be tough, especially if you are trying to fit in with family or friends or have a late dinner reservation, but it might be worth the sacrifice if you are trying to get to sleep earlier. I therefore give the applicability of this strategy a 17/25.
IS IT SCIENTIFIC?
Not exactly. A 2017 study by Kleiser and colleagues looked at 1050 participants between 13 and 81 years of age and found a significantly shorter sleep duration was present with higher alcohol consumption, higher coffee or black tea consumption and higher carbonated beverages consumption. No significant association were found for other dietary intake and sleep duration or quality (Kleiser et al., 2017).
Eating your main meal earlier in the day can lead to greater weight loss than eating later in the day, but it does not significantly impact sleep duration (Ruiz-Lozano, Vidal, de Hollanda, Scheer, Garaulet & Izquierdo-Pulido, 2016).
For individuals with obstructive sleep apnea (OSA), there does seem to be some benefits to increasing whole grain and legume consumption (Lamprou et al., 2017). It is also important that they try to reduce refined grain, red meat and soft drink consumption, as too much of these foods can lead to insulin resistance (Lamprou et al., 2017).
I therefore give the science of this strategy a 25/50.
Overall, reducing work-time and winding down in the two hours before bed as a way to sleep better gets a score of 15/25 + 17/25 + 25/50 =
WHAT I RECOMMEND
In my session one handout that I give to clients I include Sleep Hygiene recommendations from Perlis and Youngstead (2000). They have this to say about food:
“Eat regular meals and do not go to bed hungry. Hunger may disturb sleep. A light snack at bedtime (especially carbohydrates) may help sleep, but avoid greasy or heavy foods.”
–Perlis & Youngstead (2000).
The National Sleep foundation recommends that a small snack consisting of both protein and carbohydrates in the last hour before bed is generally the best, such as peanut butter on toast or cheese and crackers.
Even if what we eat doesn’t help sleep too much I have no doubt that eating less processed foods and more fresh vegetables would be good for our overall health and vitality.
If you aren’t sleeping well and want to improve it, changing your diet is unlikely to be the most effective thing that you can do. If you eat badly on one night, it’s unlikely to lead to a horrible night’s sleep. A more important factor might be how much you begin to worry about what you ate, and how much you then worry about not sleeping well.
As with most things, try to relax and wind down at night, wait until you feel sleepy before going to bed, and try not to force yourself to sleep once you are in bed. The more you try to sleep, the less likely it is to come. If you can keep your focus on something peaceful, calming or relaxing instead, you will drift off when the time is right.
Dr Damon Ashworth