Eating too close to bedtime can have a direct effect on your quality and quantity of sleep. In particular, eating right before sleep can throw off the body’s internal clock, called the circadian clock, which manages our sleep/wake cycles. Circadian rhythms can be described as the physical, behavioral and biological cycles the body follows in a day, and this rhythm is triggered by the periods of daylight and darkness. This rhythm not only affects humans, but impacts most every living thing, from plants to tiny microbes. The body’s master biological clock is located in the suprachiasmatic nucleus (SCN) in the hypothalamus portion of the brain. Circadian rhythms keep your digestive system moving round the clock, controls sleep patterns, and eating behavior. We, as humans, are unique in that we can shift our eating and sleep patterns based on convenience, work schedules, dietary needs etc.
When eating, sleeping or resting does not occur according to the circadian rhythms, cells get confused, chemicals and hormones get released at the wrong time. Fatigue and disruption to the balance of the sleep cycle is a negative byproduct of this. So timing is very important! Aim to eat your last large meal about three to four hours prior to going to bed. This gives the body plenty of time to digest and recover before it eases into sleep.
It’s not just the full stomach that poses a problem, but what you eat as well that can trigger sleep issues. First, a meal high in fat right before bed can cause bloating and discomfort. Spicy and fried foods can trigger heartburn or can cause gastroesophageal reflux disease (GERD). GERD is a condition in which the acid from the stomach comes up into the esophagus, causing irritation, regurgitation of food, a sore throat and difficulty swallowing. This irritation of the lining of the throat causes inflammation which tightens the airway making it smaller and more susceptible to collapse. Imagine how often you may be waking up feeling the effects of these symptoms and how disruptive it would be to your sleep quality. Eating late also aggravates Obstructive Sleep Apnea (OSA) and other sleep related breathing disorders (SRBD) by causing inflammation in the airway. This makes the airway smaller that creates more snoring and difficulty breathing. Why all the concern over inflammation? Chronic inflammation places our body and our immune system in a constant fight mode. Like little pac-man, our immune response defends the body and over time they start to eat up and cause damage to healthy cells and tissues too!
Sugar should be avoided as much as possible at any time any time of the day, but especially before bed. Sugar has been shown to reduce sleep quality leading to more restless, disrupted sleep as it is a major cause of inflammation in the body. Sleep and inflammation are both regulated by our circadian rhythms and are connected in such a way that when one goes awry the other tends to follow. Diets high in sugar mean you spend less time in deep, restorative phases of sleep (N3), which is the sleep stage that is imperative for healing of and restoring the body. For example, poor sleep will lead to increased inflammation in the body as it triggers a response from the sympathetic nervous system (SNS) and cortisol production. The SNS activates what is often termed the “fight or flight” response, which increases oxidative stress. This chronic, low grade inflammation is a predictor of many diseases such as cancer, heart disease, diabetes, obesity and immune issues. Conversely, inflammation leads to poor sleep. The cells that are released in the body in response to inflammation, called cytokines, play a role in sleep quality. Cytokines aid in regulating immunity and inflammation, and when they are elevated, they have been linked to trouble sleeping and insomnia.
A diet high in sugar not only causes chronic inflammation, it also affects our gut microbiome, which is a major predictor of health. There is an additional link between the health of the gut microbiome and sleep. Our gut has its own nervous system, the enteric nervous system (ENS), that releases neurotransmitters, hormones, and keeps foreign invaders out of the body. However, imbalances in this delicate environment can lead to some very harmful conditions. For instance, leaky gut syndrome is a digestive condition that affects the lining of the intestines. In leaky gut syndrome, gaps in the intestinal walls allow bacteria and other toxins to pass into the bloodstream, increasing inflammation and the body’s need to fight off foreign invaders. As the gut microbiome is also regulated by circadian clock, and inflammation affects sleep quality, this brings us back full circle; sugar affects inflammation, which in turn affects the gut microbiome, ultimately affecting sleep quality and quantity. Lastly, sugar begets more sugar. High sugar diets lead to increased sugar cravings. As mentioned earlier, sugar throws off your system and hormonal balance. This makes you more likely to reach for a late night snack, which then disturbs your sleep phases, making it harder to fall asleep, thus making your sleep quality poor. A horrible, vicious circle to say the least.
Smaller, lighter snacks are fine right before bed if it has been 5 or more hours since you have eaten. However, stay away from foods that compromise sleep! Anything containing caffeine, like green tea and chocolate, will push back the natural sleep cycle and stimulate you before going to bed. Additionally, stay away from gluten and dairy, or anything you may be sensitive to. Dairy is mucus producing, so it tends to make breathing out of the nose more challenging. And foods that cause sensitivities can cause the nasal passages to swell and therefore decrease ability to breathe through the nose.
Sleep, immune function and inflammation all carry a common regulator- our circadian clock! It is important our body has the opportunity to rest and repair rather than fight off inflammation. We can help ourselves and our bodies accomplish this by paying attention to what is going in our mouths and at what time. I get it, life is fast paced and schedules get thrown off all the time, particularly with career minded working women and mothers. But I guarantee you, the better you can stick to a schedule with food, the better quality of sleep you will get. If you find that you still have issues even after you have addressed your eating habits before bed, it may be time to consider an underlying sleep disorder. Symptoms of a sleep or breathing disorder may include: snoring/pauses in breathing witnessed while sleeping, daytime sleepiness, fatigue, depression, difficulty concentrating/brain fog, weight gain or difficulty controlling weight, and cardiovascular disease, which is not a symptom, but there is such a strong correlation between the two I think it bears mentioning. It’s time to take our sleep seriously.