We’re all doing our best to eat healthfully and sleep well, to have more energy, increase our focus and performance during the day, and protect our health over the short- and long-term. There are really powerful links between how we sleep and how we eat. Our food choices affect sleep quality and sleep amounts. And the quality and duration of our nightly rest has a big impact on eating habits. Staying rested helps keep weight and metabolism on track, and enhances our ability to make healthful choices about the foods we eat. On the other hand, when we’re tired and sleep-deprived, maintaining a healthful diet (and a healthy weight) gets a lot harder.
There’s another important factor to consider when looking at the relationship between our sleep patterns and our eating habits. And that is TIME. The timing of eating matters—for digestive and metabolic health, for weight control, and for sleep.
Here are 7 important things to know about how sleeping, eating, and time are connected to a healthier, more rested you.
- There’s no one-size-fits all prescription
Diet, nutrition and sleep intersect in complex ways that differ from one person to the next, depending on age, lifestyle and activity levels, health, and genetics. Add chronobiology to the mix—that’s the science of our daily chrono-rhythms, which regulate sleep, digestion, appetite and much else of the body’s daily functioning—and things get really individualized.
There’s a huge and ever-growing, body of research about how different diets affect health, longevity, weight, and sleep. Amid all this data, it can seem as though the “right” prescription for eating well is changing all the time. Is the Mediterranean diet the only way to go? Should I try Keto? Paleo? Do I need to be practicing intermittent fasting? Go vegetarian, or vegan? Can somebody please just tell me, are carbs my enemy or my friend? It can be overwhelming.
Let me try to simplify this a little bit right up front. Do your basic research. Pay attention to your body and how it responds to your diet—not only in terms of energy and performance, but also in relation to your sleep. Focus on eating whole foods, and make plant-based foods a foundation of your daily diet. Limit sugar, and heavily processed foods. And pay as much attention to the when of your eating as to what you eat.
- Nutrition has a big impact on sleep quality and sleep quantity
Before we jump into the when, let’s look quickly at the what of eating, as it relates to sleep. Broadly speaking, diets filled with fiber, moderate amounts of complex carbohydrates, plenty of high-quality protein and healthy fats are associated with more deeply restful, restorative, and plentiful sleep, with fewer awakenings and less risk for insomnia. The Mediterranean diet achieves this balance of macronutrients (protein/fats/carbs) and has been shown in a strong body of research to help protect against short sleeping and insomnia symptoms, and to promote high quality sleep.
Very low carb and high protein or high fat diets are popular right now—I’m taking about eating regimens like Keto and Paleo diets. There’s not enough science yet to really know how these diets affect sleep over the long term—but there are definitely short-term changes to you sleep that are important to understand if you’re eating on these regimens. Here’s some more detailed discussion on how keto and paleo diets impact sleep. No matter what eating strategy you’re working with, it’s the quality of your diet—and how your body responds to the balance of nutrients you’re consuming, including your sleep—that is most important.
There are specific foods that are excellent for both sleep and circadian rhythms, including:
Omega-3 fatty acids, found in fish, grass-fed animal proteins, nuts and seeds, vegetable oils and leafy green vegetables, promote sleep quality and support healthy circadian rhythms. I’ve written about the sleep-boosting benefits of omega-3s here.
The Vitamin B family, in particular B12, helps the body produce melatonin, which works to keep circadian rhythms and sleep-wake cycles on track.
Vitamin D helps regulate sleep-wake cycles and activates genes that control the body’s circadian clocks. Low Vitamin D levels have been linked to short sleeping.
One of my favorite foods to recommend for better sleep? Tart cherries. They’re a potent source of melatonin and have been shown to increase melatonin levels in the body as well as to reduce nighttime awakenings and symptoms of insomnia, and to increase sleep amounts.
Kiwi fruit has also been shown to increase sleep amounts, reduce nighttime awakenings and shorten the time it takes to fall asleep.
- Knowing your chronotype is essential to optimizing your eating routine
The when of eating is so often overlooked, when it’s critically important to sleeping well, staying at a healthy weight, and protecting your overall health. When you’re not sleeping AND eating in sync with your chrono-rhythms, you’re more likely to:
- be overweight (and especially to carry weight in your midsection)
- have digestive problems
- have dysfunction in your metabolic system (which can lead to heart disease and diabetes)
have sleep problems
Understanding your individual chronotype gives you a roadmap for when to eat, when to sleep—and when to do most everything else you do on a daily basis. Early rising Lions, for example, are best suited to eat breakfast a full two hours before night-preferring Wolves (who may not be inclined to eat breakfast at all. More on breakfast in a minute.) And those same Lions ought to wrap up dinner well ahead of Bears, Dolphins, and Wolves in order to finish eating a full 3 hours before bed. That’s a smart habit for all chronotypes.
Don’t know your chronotype? Take this short quiz to find out whether you’re a Lion, a Bear, a Wolf or a Dolphin.
Another chrono-strategy to consider when thinking about the timing of your daily eating routine and how it affects your sleep? Following a daily eating restriction rhythm. That can mean confining your eating to within an 8- or 12-hour window. It can also mean using more aggressive intermittent fasting schedules. Eating restriction schedules can boost weight loss. They also can reinforce circadian rhythms. That’s because as with light, food intake signals the body’s circadian clocks. Eating regularly—every 4 hours—within an 8 or 12-hour window can help keep those clocks aligned with one another and in sync, in relation to the 24-hour day. Restricting eating to these windows also allows the body ample time to be in “rest and digest” mode, and for the digestive system to power down, which is helpful for sleep and cardiometabolic health.
Here’s a recent rundown on how intermittent fasting works, and how it may affect your sleep.
- Consistency is KEY
I talk a lot about how important it is to maintain a consistent sleep-wake routine, from one day to the next. This is one of the pillars of healthy sleep throughout a lifetime, helping keep circadian rhythms on track and helping to avoid accumulating a sleep debt. A consistent sleep schedule also helps regulate appetite, and lessen cravings for the foods that disrupt sleep and contribute to weight gain—foods filled with sugar and saturated fats, and lots of heavily processed foods filled with “empty” carbohydrates.
Consistency matters to eating routines, too. Consistent eating patterns are linked to lower calorie consumption, and a lower risk for obesity. When you eat consistently at the same, optimal times day after day, you’re sending the same messages to the clocks of your digestive system, keeping them in sync. (It’s like having an old-school watch that’s always fully wound, and keeps exactly the right time, day after day.)
It’s not just the when of eating that matters. After you’ve established the optimal times for you to eat, it’s important to stick with that routine consistently, in the same way you stick to your routine bedtime and wake time.
- Personality plays a role in chrono-nutrition
There’s scientific research that now shows that different personality traits are associated with having an easier—or a harder—time sticking with a consistent eating schedule. Different chronotypes have different temperaments and personality traits that have a direct impact on eating, nutrition, and sleep. A just-released research analysis found that conscientiousness is the trait most closely associated with the ability to maintain a consistently timed eating schedule. Conscientious types also have the most success in controlling emotional eating and practicing restraint with their diets.
Early types—the Lions of the world—tend to conscientious by nature. This chronotype is, to a degree, set up by chronobiology to be naturally adept at sticking to a regular eating schedule and eating healthfully. Impulsive Wolves (evening types) and restless Dolphins (short, irregular sleepers), tend to be less primed by their personality traits to maintain consistency in their eating routines. Bears, as they always do, fall somewhere in the middle. Bears tend to be comfort seekers, and may find it challenging not to over-eat (especially those comforting, rich carbohydrates) and to limit their food intake to certain windows of the day.
All types can adopt and maintain a consistent eating routine that aligns with their chronotype. Depending on personality, some types may find it takes a little more effort to establish the habit. It’s worth the extra work to get there.
- The timing of eating affects gut health
Regular readers know I talk a lot about the microbiome, and its relationship to sleep and overall health.
The composition of the microbiome—both the types of organisms and how abundant they are—directly effects our mental and physical health, influencing mood, metabolism, cardiovascular and circulatory health, as well as the immune system, and our risk for chronic disease.
The gut microbiome is often referred to as the “second brain.” That’s because the gut is home to a nervous system and about 100 million neurons. The nervous system of the microbiome is in constant communication with the brain and our central nervous system. The microbiome is responsible for producing some of the body’s melatonin supply, as well as other hormones and neurotransmitters involved with sleep, including dopamine, serotonin, and GABA .
Our microbiome is regulated by circadian rhythms. We know from scientific research that when circadian rhythms are disrupted, and sleep is irregular, the health and functioning of the microbiome suffers: we have more unhealthful microorganisms and fewer healthful ones. And recent research suggests that the timing of daily food consumption has effects on both the composition and functioning of the gut microbiome.
Establishing regular times for eating, optimizing those times to align with your circadian biology (aka using your chronotype to set your daily eating schedule) and allowing sufficient time for the body to fast overnight (by not eating late at night and close to bedtime) may help you keep your gut stocked with more health-promoting bacteria.
Here’s some guidance about the prebiotic foods that support beneficial bacteria in the gut, and give a boost to sleep.
- Short sleepers have distinct eating patterns
Not getting enough sleep alters the hormones in the body that regulate appetite, increases cravings for salty, fatty, sugary foods, and increases overall daily calorie intake. People who don’t sleep enough get more of their calories from fat, and do more snacking than longer sleepers do. Short sleepers have been shown to eat a narrower range of foods than people who get sufficient nightly rest.
They also spend more time eating during the windows of time when they would otherwise be sleeping, if their sleep weren’t restricted. For many people who don’t get enough sleep, that means eating late at night, which is associated with risks for weight gain and metabolic dysfunction, with acid reflux (GERD), and with trouble sleeping.
What defines a short sleeper? Different studies will define this category differently. Many studies define short sleep as getting less than 7 hours a night. Nightly sleep needs vary from individual to individual. Not everyone needs 8 hours of sleep a night, or even 7. Most adults do need somewhere in the range of 7-9 hours nightly, to feel rested and function at their best. Some of the hallmark symptoms of insufficient rest are:
- having trouble waking up in the morning
- feeling tired and lacking energy during the day
- having trouble focusing, and with memory
- experiencing ups and downs with mood
In addition, eating habits like the ones I’ve described above can be a sign you’re not getting enough rest.
The when of sleeping AND of eating is so important to your ability to function and feel at your best. Paying attention to the timing of your daily dietary habits can make it easier to stick to a healthful diet and boost your sleep, too.
Michael J. Breus, PhD, DABSM
The Sleep Doctor™