How Does Diet Affect Sleep? | The Relationship of Food and Quality Sleep

I was originally going to write an article on the top foods that promote quality sleep. But that turned out to be a challenge. Let me explain:

It’s easy to find lists of the top foods for sleep. However, most of these articles are weak on scientific facts and data. Or if they do provide some science, it is extremely general and often short on any in-depth analysis. Scientific facts are important to me, so I had to revise my strategy.

Instead, I decided to research how diet, in general, affects sleep. Surprisingly, there isn’t a lot of clinical research on this either, but at least I was able to get more concrete information to share with you.

Which leads me to today’s topic of: how does diet affect sleep?

Summary: our diet and food intake before bed can affect our sleep and sleep quality. Research suggests that eating too close to bedtime negatively affects sleep patterns, particularly in women. Additionally, certain nutrients can positively or negatively affect our ability to fall asleep quickly and stay asleep. Finally, quality sleep and a healthy diet have long been linked to maintaining proper health.

(If you’d like to see this content in a video, watch my YouTube video here.)

Basic Terminology

Before we begin our discussion, we need to learn some basic terminology. Most, if not all, of these terms are familiar, but we should know these definitions in order to fully understand this topic.

Let’s start with two terms related to sleep: sleep latency and sleep efficiency.

Sleep latency (also known as sleep onset latency) is the amount of time it takes someone to go from being fully awake to sleeping. Ideally, this process begins as soon as you get into bed and turn out the lights. Sleep latency should take less than 30 minutes to be considered “good,” and a sleep latency time of longer than 30 minutes is a clinical checkpoint for those who may have insomnia. Diet and other factors, such as using your phone in bed, can negatively affect sleep latency.

Sleep efficiency is the percentage of time a person spends sleeping relative to the total amount of time in bed. Normal sleep efficiency is considered 80%, so if you are in bed for a total of 10 hours, you should be asleep for at least 8 hours.

And let’s quickly review some basic terms regarding our diet and nutrients:

Macro-Nutrients: provide calories (energy); the three macro-nutrients are carbohydrates, protein, and fat.

Carbohydrates: sugars, starches, and fibers found in grains, fruits, and vegetables.

Protein: building block of muscle mass, commonly found in animal products, but also nuts and legumes.

Fat: provide energy storage, and there are good and bad kinds of fat in our diets.

When to Eat Before Bed

For the rest of this article, I will be using two published studies from the Journal of Clinical Sleep Medicine as sources (linked below). The first study, from 2011, discusses the relationship between food intake and sleep patterns. The second study, from 2016, discusses the affects of fiber and saturated fats on sleep quality.

Research has shown that eating in close proximity to going to bed can negatively affect your sleep. High calorie foods consumed before bed, especially 30-60 minutes before bed, increases sleep latency. This means it takes longer for someone to fall asleep, and this is especially true for women.

Eating too close to bedtime has a few other negatives. First, eating kick-starts your metabolism, a process that raises your body temperature. Our bodies decrease their internal temperature in preparation for, and during, sleep. Second, eating right before bed will increase your gastric volume (the amount of food in your stomach), which could create physical discomfort.

Finally, eating too close to bedtime can change our body’s metabolic and nutritional cycles. Studies have shown that eating before bed can alter our sleep patterns, which in turn adjusts our body’s appetite sensations. In other words, our body may mistakenly think we are hungry when we otherwise shouldn’t be due to an interrupted circadian rhythm. This can lead to overeating, as well as our body storing excess fat.

It is generally recommended to eat your last large meal no later than 4 hours before bed. There is no consensus as to how late a snack can be eaten before bed.

What Not to Eat Before Bed

Studies have found eating foods that are high in saturated fats and low in fiber (either before bed, or throughout the day) reduce sleep quality. This includes both sleep latency and sleep efficiency. Additionally, high intakes of sugars and simple carbohydrates increase your chance of waking up during the night. Simple carbohydrates have sugar in them and are used as quick energy for the body. These are often found in fruits, as well as processed candy.

Avoiding simple carbohydrates before bed is important for another reason. Since simple carbohydrates are used up by the body quickly, eating these foods right before bed means you will not remain satiated (feeling full) throughout the night. This can further alter your body’s appetite cycle.

Another general consideration is to avoid saturated fats (bad fats) as much as possible. This is important for overall health, but it also affects sleep. Diets which are high in saturated fats not only increase sleep latency, but also decrease the amount of time spent in slow wave sleep. Slow wave sleep, or when your brain emits delta waves, is when our body is in deep, dreamless sleep and restoring itself.

To learn more about delta waves and sleep, read my article here.

What You Should Eat Before Bed

Now that we know what not to eat, let’s discuss some good, sleep-approved options. Keep in mind that I will provide general guidelines, rather than a specific diet.

I stated above that research suggests you eat your last large meal no later than 4 hours prior to going to bed. This meal should be rich in complex carbohydrates that are high on the glycemic index. Examples include whole grain bread, brown rice, and potatoes.

Additionally, this meal should include high-quality lean proteins, such as chicken, turkey, or fish. Finally, your meal should include good fats, such as omega 3 and 6 fatty acids, which can be found in fish or nuts.

So what do you notice about the kinds of foods that are good for sleep?

It’s a well-balanced diet! Eating high-quality healthy foods, in the right proportions, are essential to our overall health, and that includes sleep. Keeping our bodies in balance is much easier when we provide it the right kind, and the right amount, of nutrients.

As a personal example, I recently (by coincidence) started eating Kashi brand cereal, which is high in fiber. Since I’ve been eating Kashi cereal, my sleep has improved just enough for me to notice it. After doing research for this article, it makes since that my sleep had improved a little bit since my diet was including more high-quality fiber. My sleep quality is still no where near perfect, but this means I need to adjust my diet even more.

What snacks Should I Eat Before Bed?

Science has not defined precisely which foods you should eat before bed, nor have they come to a consensus on how close to bedtime you can eat these snacks. Since I don’t have tons of research to back this information up, I will only provide a short list of foods which are generally considered good snacks to have before bed:

  • Banana
  • Low-fat yogurt
  • Eggs
  • Low-fat cottage cheese
  • Almonds
  • Herbal tea (particularly chamomile…yes, I know it’s a drink and not a snack)

Conclusion

It should be no surprise that maintaining a well-balanced diet helps improve sleep quality, just as a good diet improves many areas of our life. Keeping a healthy diet is a holistic approach to health, rather than finding a few foods that could be “quick fixes” to poor sleep.

As research continues to improve on this topic, I will be fascinated to see what other correlations can be made between diet and sleep quality.

Sources:

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