Improving Sleep Quality: What To Avoid (2023)

You may have heard that certain nutrients can impact sleep. But does this mean that foods and drinks directly hinder one’s ability to sleep?

Having a background in nutrition and dietetics, I can tell you exactly which foods and nutrients can disrupt sleep, according to research.

Foods that lead to poor sleep are often high in sugar and/or fat such as candy, smoothies and soda, full-fat dairy products, fried foods, cheeses and cured meats, and spicy foods. Caffeine, in either food or drinks, and alcohol can also disrupt sleep, depending on the amount consumed.

Knowing which foods and drinks negatively impact sleep is important as it will help you make more informed choices when it comes to getting a good night’s sleep.

• The relationship between diet and sleep regulation is complex, because of the many nutrients and hormones involved in the sleep-wake cycle and feed-fast cycle.
• There is no single food that hinders sleep. Rather, it’s the cumulative effect of your dietary habits, which may include the consumption of heavy meals close to bedtime (high in fat and sugar, and low in fiber and complex carbs).
• Research suggests that sleep-promoting foods include kiwis, tart cherry juice, nuts, and salmon, as they include nutrients that interact with sleep metabolism.

Diet and sleep are closely linked. This is because ingredients in certain foods and drinks can influence hormones and neurotransmitters involved in sleep regulation.

Sleep is regulated by a complex interaction of hormones and neurotransmitters, including serotonin, melatonin, and cortisol. They all help to regulate the so-called sleep-wake cycle.

Serotonin regulates mood and is essential for making melatonin. Melatonin (sleep hormone) helps you relax and get to sleep, whereas cortisol (stress hormone) promotes wakefulness and alertness during the day, helping you get up and feel awake.

If serotonin is low, it can lead to low mood which, in turn, interferes with melatonin production. Consequently, if melatonin and cortisol are unbalanced, they can cause insomnia and sleeplessness.

In addition to melatonin, cortisol, and serotonin, other hormones can also interfere with sleep, such as insulin, leptin, and ghrelin.

Insulin helps to regulate blood sugar levels whereas leptin and ghrelin (hunger/satiety hormones) help to regulate appetite. If blood sugars are unstable and leptin and ghrelin are unbalanced, they can lead to poor sleep and sleeping disorders.

Ultimately, your diet habits influence your hormones and can disrupt sleeping patterns which, in turn, can have a knock-on effect on food choices and eating patterns.

For example, if you don’t get enough sleep you are more likely to desire more food and opt for high-calorie foods.

Caffeine is a stimulant that causes you to be more alert and awake.

It can influence sleep quality if taken more than you can tolerate, or if taken later in the day or close to bedtime (within 6 hours of bedtime).

According to the U.S. Food and Drug Administration recommendations, the safe amount of caffeine is 400 mg daily.

Here are some examples of foods and beverages that contain caffeine, taken from the U.S. Department of Agriculture Food Data Central:

• Coffee: one 240 ml coffee contains around 80-100 mg of caffeine. So if you usually have 4 cups of brewed coffee in a day, this is your upper limit of caffeine.
  
• Tea: a 240 ml cup of green or black tea contains 30-50 mg (herbal teas are caffeine free).
  
• Chocolate: a 28 gram serving contains around 9-12 mg of caffeine, meaning that a 100 g chocolate tablet contains around 30-40 mg.
• Coffee flavoured ice cream: this ranges from 30-70 mg per 240 ml. For example, Ben & Jerry’s Coffee ice cream contains 70 mg whereas Haagen-Daz contains 30 mg.
  
• Energy drinks: caffeine can range from 40-250 mg in energy drinks. For example, a 250 ml can of red bull contains 80 mg of caffeine, and a 473 ml can of monster contains 160 mg.
  
• Soft drinks: a 360ml bottle typically contains 30-40 mg of caffeine. This includes diet soft drinks as well as full sugar, for example diet pepsi and pepsi cola
  
• Pre-workout supplements: one pre-workout serving contains between 200-420 mg of caffeine, so this means it is very easy to go over the upper limit if you have other caffeine-containing items in the day.

Tyramine is an amino acid (protein) that promotes the production of stimulants (norepinephrine, adrenaline). It is made in the body but it is also present in a number of food products. High amounts in the body are linked to migraines and insomnia.

Tyramine is present mostly in aged and fermented (longer shelf life products with added preservatives and salt) foods and beverages. Consider that 6mg of tyramine in any 30g serving of food is considered high.

Here’s a list of high tyramine foods:

• Matured cheeses: blue cheeses (Camembert, Stilton and Gorgonzola) and hard cheeses (Cheddar, Parmesan, and Emmentaler)
  
• Cured meat/fish products: smoked hams, salamis, dry-type summer sausages, mortadella, jerky, and pickled or smoked fish
  
• Alcoholic beverages: beers which are home-made or unpasteurized, European or Korean
  
• Overripe/spoiled fruits and vegetables: overripe bananas and avocados, pickled vegetables (kimchi or sauerkraut)

Sugary foods are commonly high in simple and refined carbs and make you hungry soon-after because they are not filling and low in fiber. As such, they cause blood glucose levels to spike and drop.

“Low fiber and high saturated fat and sugar intake is associated with lighter, less restorative sleep with more arousals” Marie-Pierre St-Onge – Journal of Clinical Sleep Medicine

This means that overconsuming sugary foods (added sugar included) is linked to disrupted sleep (consider that the upper daily limit for added sugar intake is 10% of your total calories).

Common foods high in sugar that can impact sleep include:

• Sweetened beverages: full sugar soda, fruit juices, smoothies, red bull, monster.
  
• Sweets/candy: gummies, jelly beans, pralines such as Mon Cheri and Pocket Espresso, sugar coated dried fruits or nuts, chocolate/nut spreads, jam, honey, white table sugar, maple syrup and agave syrup.
  
• Some sport supplements: sports chews, simple sugar gels, dextrose powder, gatorade, and lucozade.
  
• Bakery products: waffles, doughnuts, pastries, cookies.

Spicy foods are linked to poor sleep because they can cause heartburn and indigestion if eaten close to bedtime. This might be because lying down allows acids to creep up, which can become worse while sleeping.

Body temperature elevation after eating spicy food can also be another reason for poor sleep.

So, try to avoid (if you can) spicy foods late in the evening close to bedtime (1-2 hours is close).

Here are a few examples of spicy foods:

• Chili peppers: ghost pepper, jalapeño, serrano, and Thai chili peppers
  
• Spicy meals: curries, kimchi, tom yum soups, and ramen noodles
  
• Sauces/condiments: tabasco, mustard, wasabi, sweet chili sauce, spicy olive oil, hot sauce, buffalo sauce
  

High fat foods, especially high in trans fats and saturated fats, can interfere with sleep quality.

This is because fat is more complex to break down and digest than other nutrients as it takes 3-4 hours to digest. Lots of fat in a meal also means that your meal is calorie dense resulting in a heavy meal before bed.

Consider that fat intake should be roughly 20-35% of your total daily calories (depending on your goals and training), with no more than 10% of this from saturated fats.

Here’s a list of high-fat foods to limit especially before bed:

• Fried foods: pastries, burgers, fries, pizza, and doughnuts.
  
• Full-fat dairy products: yogurts, whole milk, cream, and cheese.
  
• Cured and fatty meats: chicken skin, bacon, chorizo, salami, pancetta, and sausages.
  
• Oils/spreads: butter, ghee, suet, lard, and coconut oil.

Alcohol acts as a sedative and interacts with neurotransmitters in the brain. It is quickly absorbed in the bloodstream to reach the liver, however your liver can only process a little amount at a time.

This means that the excess alcohol will circulate throughout the body (depending on the person and quantity of alcohol consumed, alcohol can circulate in the body for various hours).

If alcohol is also taken with caffeine or energy drinks, it hides the sedative effect of alcohol, which commonly makes people drink more.

For these reasons, any amount of alcohol can cause disrupted sleep, even if it induces feelings of sleepiness at first.

My advice would be to limit alcohol consumption, especially close to bedtime. Try to stop drinking alcohol at least four hours before bedtime to avoid sleep disruptions.

Heavy meals consisting mostly of fatty and sugary foods is associated with interrupted sleep. This is because of the more complex digestion demands attributed to heavy meals.

The digestion of these meals can take several hours, and if you go to sleep on a full stomach there may be a higher risk of heartburn or indigestion.

To avoid this, aim to give your body time to digest. If you can, after a meal wait 3-4 hours before you go to sleep.

Try having lighter meals rich in fiber (vegetables and wholegrains), protein (meat, eggs, fish, or pulses) and complex carbs (brown bread, brown pasta, quinoa) which will give you longer lasting energy before sleeping.

For example:

• 90-110g cooked chicken filet, 3-4 egg sized boiled potatoes with skin on, steamed broccoli and cauliflower.
• 140g grilled salmon filet with 90g cooked quinoa and asparagus.
• 2 slices of brown bread, 2-3 scrambled eggs mixed with tomatoes and mushrooms.