By Dr. Mercola
Nearly 41 million US adults are sleeping just six hours or less each night, putting them at risk of adverse health effects (such as heart disease and obesity) and potentially fatal drowsy driving linked to lack of sleep.1
While stress is one of the most-often cited reasons why people can't sleep, there's another factor that could be keeping you up at night: your diet. Certain foods can significantly interfere with your sleep, including the five worst of the worst below.
What Are the Five Worst Foods for Sleep?
A drink or two before bed can make you drowsy, leading many to believe it's actually beneficial for sleep. But while it may make you nod off quicker, research shows that drinking alcohol makes you more likely to wake during the night, leaving you feeling less rested in the morning.
The latest study found that alcohol increases slow-wave "deep" sleep during the first half of the night, but then increases sleep disruptions in the second half of the night.2
Since alcohol is a potent muscle relaxant, it can also increase your risk of snoring. Snorers -- and their bed partners -- often experience restless sleep leading to sleepiness and difficulty concentrating during the day.
Coffee, of course, is one of the most common sources of caffeine. This stimulant has a half-life of five hours, which means 25% of it will still be in your system even 10 hours later, and 12.5% 20 hours later (see the problem?). Plus, in some people caffeine is not metabolized efficiently, leaving you feeling its effects even longer after consumption. So, an afternoon cup of coffee or tea will keep some people from falling asleep at night. Be aware that some medications contain caffeine as well (for example, diet pills).
3. Dark Chocolate
Dark chocolate, though the healthiest form of chocolate from an antioxidant perspective, can contain relatively high levels of caffeine that can keep you up at night if you're sensitive. It also contains theobromine, a compound that has caffeine-like effects.
4. Spicy Foods
Spicy foods before bedtime can give you indigestion that makes it nearly impossible to get a good night's sleep. But even if you can eat spicy foods without discomfort, they are still linked with more time spent awake during the night and taking longer to fall asleep.3 It's speculated that this may be due to capsaicin, an active ingredient in chili peppers, affecting sleep via changes in body temperature.
5. Unhealthy Fatty Foods
When you don't get enough sleep, you're more likely to crave high-fat, high-sugar foods the next day. But eating a high-fat diet also has impacts on your sleep, including leading to more fragmented sleep. In fact, an animal study revealed that eating fatty foods may lead to disrupted sleep and excessive daytime sleepiness.4
The link may be due to the brain chemical hypocretin, a neurotransmitter that helps keep you awake and also plays a role in managing appetite. Keep in mind that while you should limit your intake of unhealthy fats like those from fried foods, healthy fats (including saturated fats) play an important role in your diet and shouldn't be eliminated.
Recent Study Gives Clues on How Diet Impacts Sleep
The link between what you eat and how well you sleep, and vice versa, is only beginning to be explored, however, a recent study evaluating the diets and sleep patterns of more than 4,500 people did find distinct dietary patterns among short and long sleepers.5
While the study was only able to generate hypotheses about dietary nutrients that may be associated with short and long sleep durations, it did yield some interesting data.
- Very short sleepers (less than 5 hours a night): Had the least food variety, drank less water and consumed fewer total carbohydrates and lycopene (an antioxidant found in fruits and vegetables).
- Short sleepers (5-6 hours): Consumed the most calories but ate less vitamin C and selenium, and drank less water. Short sleepers tended to eat more lutein and zeaxanthin than other groups.
- Normal sleepers (7-8 hours): Had the most food variety in their diet, which is generally associated with a healthier way of eating.
- Long sleepers (9 or more hours): Consumed the least calories as well as less theobromine (found in chocolate and tea), choline and total carbs. Long sleepers tended to drink more alcohol.
As for what the data means, researchers aren't yet sure, but it could be that eating a varied diet is one key to normal, healthful sleep. If you need some help in this area, check out my nutrition plan for a step-by-step guide to optimizing your eating habits.
Sleep Tip: Stop Eating at Least Three Hours Before You Go to Bed
It is ideal to avoid eating any food three hours before bed, as this will optimize your blood sugar, insulin and leptin levels and contribute to overall good health and restful sleep. Specifically, avoiding food for at least three hours before bed will lower your blood sugar during sleep and help minimize damage from too much sugar floating around. Additionally, it will jumpstart the glycogen depletion process so you can shift to fat-burning mode.
A recent study6 is a powerful confirmation of this recommendation, as it found that the mere act of altering your typical eating habits — such as getting up in the middle of the night for a snack — causes a certain protein to desynchronize your internal food clock, which can throw you off kilter and set a vicious cycle in motion. Eating too close to bedtime, or very late at night when you'd normally be sleeping, may throw off your body's internal clock and lead to weight gain.
Routinely eating at the wrong time may not only disrupt your biological clock and interfere with your sleep, but it may also devastate vital body functions and contribute to disease.
That said, while you've likely heard the advice that breakfast is the most important meal of the day, some experts believe that skipping breakfast and eating your main meal at night may actually be more in-tune with your innate biological clock. I've revised my own eating schedule to eliminate breakfast and restrict the time I eat to a period of about six to seven hours each day, which is typically from noon to 6 or 7 pm.
Diet Is Only One Factor in Getting a Good Night's Sleep
There are many variables that impact how well you sleep. I suggest you read through my full set of 33 healthy sleep guidelines for all of the details, but to start, making some adjustments to your sleeping area can go a long way to ensure uninterrupted, restful sleep.
- Cover your windows with blackout shades or drapes to ensure complete darkness. Even the tiniest bit of light in the room can disrupt your pineal gland's production of melatonin and the melatonin precursor serotonin, thereby disrupting your sleep cycle.
So close your bedroom door, get rid of night-lights, and refrain from turning on any light during the night, even when getting up to go to the bathroom. If you have to use a light, install so-called "low blue" light bulbs in your bedroom and bathroom. These emit an amber light that will not suppress melatonin production.
- Keep the temperature in your bedroom at or below 70 degrees F (21 degrees Celsius). Many people keep their homes and particularly their upstairs bedrooms too warm. Studies show that the optimal room temperature for sleep is quite cool, between 60 to 68 degrees F (15.5 to 20 C). Keeping your room cooler or hotter can lead to restless sleep.
- Check your bedroom for electro-magnetic fields (EMFs). These can also disrupt your pineal gland's production of melatonin and serotonin, and may have other negative effects as well. To do this, you need a gauss meter. You can find various models online, starting around $50 to $200. Some experts even recommend pulling your circuit breaker before bed to kill all power in your house.
- Move alarm clocks and other electrical devices away from your head. If these devices must be used, keep them as far away from your bed as possible, preferably at least three feet.
- Reduce use of light-emitting technology, such as your TV, iPad, and computer, before going to bed. These emit the type of light that will suppress melatonin production, which in turn will hamper your ability to fall asleep, as well as increase your cancer risk (melatonin helps to suppress harmful free radicals in your body and slows the production of estrogen, which can contribute to cancer). Ideally, you'll want to turn all such light-emitting gadgets off at least one hour prior to bedtime.