Can what you eat impact your sleep?

Sleep and food have a fascinating and interconnected relationship.

Studies have shown that if you skimp on sleep, you are likely to find yourself making poor food choices. Inadequate sleep leads to junk food cravings, eating more calories, and experiencing more hunger, much to the detriment of your healthy eating plan. 

“Not getting sufficient sleep might undermine your weight loss efforts,” says Dr. Gracen Lake, MD. “Inadequate sleep is associated with poor food selections, feeling more hungry and consuming more calories, engaging in less physical exercise, and eventual weight gain.”

Sleep matters whether you’re simply trying to pick up healthier eating habits or want to shed a few pounds. Here’s what you need to know about the relationship between food and sleep.

When to Eat for Better Sleep

If you want to optimize sleep, it’s best to avoid eating before bedtime. 

“You should avoid eating food three hours before your bedtime. Otherwise, your digestion will have to work that ‘extra shift’ leading to an upset stomach or heartburn,” says Dr. Edward Salko, a Board-Certified Physician and Medical Director of PersonaLabs. 

If your regular bedtime is 11pm, you’ll want to finish your last meal no later than 8pm. 

However, don’t eat your last meal too early in the day. 

“Eating too early and leaving too much time between your last meal and sleep can increase the risk of low blood sugar during the night,” says Dr. Chelsie Rohrscheib, head sleep expert at sleep diagnostics company Wesper. “Decades of clinical research tell us low blood sugar triggers the brain to increase activity levels to help you seek out food.”

Going to bed with a growling, empty stomach may disrupt your sleep, causing you to wake up in the middle of the night. 

Stick with the 3-hours before bed rule, and you’ll be in the sweet-sleep spot between not eating too early or too late.

Research suggests that 3 meal-timing habits are likely important for good health and sleep:

1. consistent daily eating duration of fewer than 12 hours per day
2. eating most calories in the earlier part of the day
3. avoiding food intake when melatonin levels are high: close to bedtime, while sleeping, or very early morning

Why You Want to Avoid Late-Night Snacking

Everyone’s been there: standing in front of the fridge late at night, seeking the comfort of a little midnight snack. 

Your occasional late-night snack may be warranted, but it’s not something you want to make a habit of if you’re trying to optimize sleep performance.

Eating your last meal 3 hours before bedtime allows you to eat in sync with your body’s natural circadian rhythm — the internal clocks found in just about every cell in your body that tell us when to wake, sleep, feed, and fast. 

“Your circadian rhythms control a wide range of biological processes, including your metabolism, hunger, and sleep-wake cycle,” notes Dr. Lake.

Before modern times, humans hunted and ate during the day and rested at night. Over time, our bodies developed networks of internal clocks, including ones in our digestive system (i.e., stomach, liver, and pancreas) to help us stay alert at biologically advantageous times.

Your circadian system prompts your body to be most efficient at digesting, absorbing, and metabolizing food during the day when you are active, and light is present. Your body reaches peak efficiency in the earlier phase of the day; insulin sensitivity is greatest in the morning when it’s needed to regulate blood sugar.

As evening approaches, your body produces melatonin. You may already know that melatonin sends “sleep signals” to your brain, but you may not know it also reduces insulin release and makes your body less effective at properly processing glucose.

Chowing down on a late-night hamburger or brownie confuses your internal clocks. The one in your brain sees that the sun has set and starts preparing for sleep. However, the clocks in your digestive system kick into high gear, actively digesting at the very moment your other clocks are preparing for bed.

You’ve now forced your body to sleep and digest at the same time — activities that the body has not evolved to do well simultaneously. Split your body’s attention between two tasks, and it struggles to do a great job at either one.

If you’ve ever experienced the uncomfortable burning in the chest that comes along with nighttime heartburn, you know exactly how difficult resting-while-digesting can be for your body.

How Does Fasting Impact Sleep?

Today, no conversation about meal timing would be complete without mention of fasting.

Fasting and intermittent fasting are all the rage, with proponents claiming that a fasted period can offer benefits ranging from better sleep to improving blood sugar, cognitive function, and decreasing body fat (to name a few).

Your body’s circadian system is built for fasting — you naturally fast while you sleep! 

You’ve been practicing the fasting trend your entire life and didn’t even know it.

If you stop eating before sunset, you’re encouraging your body’s natural sleep pattern by “circadian fasting.”

When you go to bed with an empty stomach, the internal clocks in your digestive system align with the clock in your brain so that all your systems agree to go offline for sleep. This kind of fasting — which you can accomplish simply by eating dinner early and avoiding snacks before bed — can unequivocally improve your sleep.

If you’re embarking on a more complex fasting protocol, your digestive clocks may need time to adjust to a new routine.

You may not see the improvements of fasting immediately, but if you stick with it, your body will adjust, and your sleep patterns will normalize.

What to Expect When You Start Fasting

When you first experiment with intentional fasting, you may experience disrupted sleep patterns. Don’t be surprised to find yourself lying wide awake in bed, bored and hungry.

As mentioned above, going to bed hungry can lower blood sugar. Signals get sent to your body: “It’s time to seek out food.” 

Your digestive clocks start trying to get your attention by shouting: “We haven’t eaten in a while! Red alert, start looking for food so we can survive!” As a result, your body might jump into action by producing the stress hormone cortisol to help keep you awake and alert, you know, just in case a bite of food happens to walk by.

“It’s important to remember that fasting triggers the brain’s starvation response, and starvation is extremely wake-promoting,” reminds Dr. Rohrscheib.

This “fasting insomnia” period is temporary — your body is simply getting used to a new routine. After an adjustment period of about 3 to 7 days, your body steadies its rhythm, and fasting begins to benefit your sleep.

The Long-term Benefits of Fasting

When you fast regularly, your body and circadian rhythm adapt to your new schedule, and you’ll experience the benefits of fasting.

“When done correctly, fasting may help to improve sleep quality by regulating the circadian rhythm,” notes Dr. Rohrscheib. “Because eating and sleep are both controlled by the circadian rhythm, controlling your food intake times with fasting can help your sleep rhythm stay on schedule.”

Intermittent fasting (eating within an 8 – 12 hour window) causes insulin to drop and levels of sleep-supporting melatonin to rise. That will help you fall asleep faster and stay asleep longer.

Fasting also promotes the release of human growth hormone, one of your body’s vital resources for repairs while you’re asleep.

Foods to Eat for Better Sleep

Now that you know when to eat to improve your sleep quality, the next question becomes:

What should you eat for better sleep?

Over the years, large epidemiological studies have found that people who suffer from consistently bad sleep tend to have poor-quality diets. Healthier diets have been linked to better sleep quality.

In one randomized clinical trial, researchers recruited 26 healthy adults. They controlled what they ate and monitored how they slept for four days. Subjects received regular meals prepared by nutritionists during this time. On the fifth day, they were allowed to eat whatever they wanted.

The researchers discovered subjects eating more saturated fat and less fiber (like you get from fruits, vegetables, and whole grains) suffered from a reduction in deep, restorative slow-wave sleep.

“Some diet patterns and specific foods are linked to improved sleep, specifically, the Mediterranean diet, which focuses on healthy fats, fruits, vegetables, whole grains, and lean protein. These foods don’t need to be consumed directly prior to sleep but throughout the day,” advises Brianne Okuszka, MPPD, RDN.

What Not to Eat When You Want to Sleep Better

If a healthy diet full of fiber, plant-based foods, and lean protein supports good sleep, what foods should you avoid?

Edibel Quintero, MD is a medical doctor specializing in obesity and nutrition. According to Quintero, oily, junky, spicy, acidic, and sugary foods should be avoided as you near bedtime. She says the biggest sleep disrupters include:

• grapefruit and citrus fruits which are acidic and can cause or aggravate heartburn 
• cheese and preserved meats which have high levels of the amino acid tyramine that can keep you alert for long hours  
• spicy foods such as curries and sauces containing capsaicin, which increases your body temperature at a time when your body is trying to reduce body temperatures in preparedness for sleep 
• ice cream and foods with sugar which interfere with blood sugar levels and release the stress hormone cortisol

The relationship between sleep and food is clear. When and what you eat can significantly impact the quality of your sleep. 

If you’re getting good sleep, your body will work optimally and support you on your weight loss goals. On the other hand, poor-quality sleep can have the opposite effect. Poor sleep signals your body to feel hungry, eat more, and crave foods that hinder weight loss. Worse, you get caught in the poor-diet, poor-sleep loop. 

Eating a healthy, Mediterranean-style diet, experimenting with intermittent fasting, and not eating within a 3-hour window of bedtime can help promote a functioning and efficient balance between your sleep and your food.

This post was written in collaboration with Ouraring.com