Find out which foods hinder your ability to sleep.

Advertisement

Sleep is an important part of any healthy lifestyle. When your body doesn't get enough sleep, it can lead to trouble focusing, can impact your memory and more. That's why getting enough shut-eye is crucial. But aside from the amount of sleep you get (FYI for adults, seven to nine hours is the amount recommended by the Sleep Foundation), the quality of your sleep is also important. And one thing that can influence the quality of your sleep is your diet. 

Portrait of woman struggling to fall asleep
Credit: Getty Images / Boy_Anupong

I reached out to three sleep experts who noted that diet's influence on quality shut-eye is as much about what you don't eat and drink as what you do. Read on to learn about five foods that could negatively impact your sleep.

Caffeine

This is arguably the biggest culprit when it comes to poor sleep. First of all, it's a stimulant—hello! Plus, research shows that caffeine suppresses melatonin production and also blocks receptors for a chemical called adenosine, which induces sleepiness—both of which can negatively affect sleep quality and quantity. A Journal of Clinical Sleep Medicine study found that ingesting 400 mg of caffeine (the equivalent of about one venti Starbucks coffee) six hours before bed significantly disrupted participants' sleep compared to a placebo—shortening the duration by more than an hour. Caffeine also hangs around in your body long after you've gulped your morning coffee. It has an average half-life of around five hours, but it can be up to 10 hours, which means that if you have a cup of joe at 3 p.m., half of that caffeine will still be in your system at 8 p.m. or later. So Michael Breus, Ph.D., one of the country's leading sleep doctors and a fellow of the American Academy of Sleep Medicine, advises cutting off your caffeine intake at 2 p.m. to make sure it's cleared out by the time you want to hit the hay.

Alcohol

"Many people drink alcohol because they think it will help them sleep," says Frank Scheer, Ph.D., a professor of medicine at Harvard Medical School and director of the Medical Chronobiology Program at Brigham and Women's Hospital in Boston. "But while it may help them fall asleep faster, the quality of sleep is going to be lower." The problem is that once the booze wears off, it has the opposite of a sedative effect—disrupting your sleep later in the night and cutting the amount of REM time you get (the stage linked to learning, memory and mood). "Alcohol almost completely obliterates stages 3 and 4 of sleep, which are tied to immune and cognitive function," says Breus. And the more cocktails you have, the worse it gets. His advice: Stick to one or two drinks max and stop drinking three hours before bedtime.

Sugar

Diets high in sugar and other simple carbs have been associated with lighter, less restorative sleep with more middle-of-the-night awakenings, according to research conducted by Marie-Pierre St-Onge, Ph.D., an associate professor of nutritional medicine at Columbia University and director of Columbia's Irving Medical Center Sleep Center of Excellence. "The mechanisms aren't totally clear, but spikes and rapid decreases in blood sugar levels may disturb sleep," she says. Eating lots of sugar can also cause inflammation, and some evidence suggests this in turn may throw off your internal body clock.

Saturated Fat

The same clinical trial that fingered sugar as an enemy of sleep also found that participants who ate diets highest in sat fat spent less time in slow-wave sleep—the "restore and recover" type. St-Onge says inflammation could be at least one of the reasons here, as well.

Spicy Foods

One small study published in the International Journal of Psychophysiology found that eating Tabasco or mustard with dinner made it harder for participants to fall asleep and reduced the overall quantity they got, as well. Fiery foods may bump up your core body temperature—which ordinarily dips by several degrees at night—and hinder sleep. Plus, they can make you more prone to acid reflux, which isn't conducive to peaceful slumber either.

This article originally appeared in EatingWell Magazine, November 2021.