Americans consume a startling amount of sugar every day. It’s in almost everything we eat, and as one scientist discovered a few years ago, it contributes more to obesity than dietary fat. At Saatva, we don’t like to rain on anyone’s parade. We love National Donut Day as much as the next person, but we’re also big fans of moderation. High sugar intake is clearly unhealthy, and—like certain other foods, including pizza and dark chocolate—it can also interfere with your sleep in several ways.
Sugar leads to poor quality sleep
How exactly does sugar affect sleep? Research on the subject is surprisingly sparse, but one study from 2016 provides strong evidence that sleep and sugar don’t mix. Scientists from several New York universities recruited 26 healthy adults and monitored their sleep, using both restricted and unrestricted diets. When the subjects were allowed to eat whatever they wanted, they consumed less fiber but more sugar and saturated fats.
The study found that subjects on an unrestricted diet had higher sleep onset latency (it took them longer to get to sleep) and lower quality sleep overall. Specifically, higher consumption of sugar and saturated fats led to less deep sleep and more arousals (instances of waking up). In other words, consuming lots of sugar means your sleep will be worse and you won’t feel as well rested in the morning.
Why does eating sugar make me tired?
You might think that sugar keeps you awake and makes you feel more energized—the much-debated (and scientifically unproven) “sugar high“—but in reality consuming sugar has the opposite effect. Research indicates that high levels of glucose inhibit an important peptide called orexin, which is responsible for feelings of alertness. With less orexin in our system, we tend to feel more tired and hungry, which is one reason why sugar also messes with our diet. Scientists found that eating protein along with sugar could limit these effects somewhat, but the bottom line is that sugar is no substitute for other, more healthy sources of energy.
Poor sleep makes the body crave more sugar
Not only does sugar lead to poor sleep, but poor sleep also affects sugar consumption. That’s because when we’re tired from lack of sleep, we tend to eat more junk. Researchers at King’s College London recruited 42 students and staff and gave them each a personal “sleep extension” plan to help improve their sleep habits. That led to longer and better sleep among study participants. What’s more, those with better sleep tended—of their own volition—to eat less sugar. “Sleep extension,” the researchers concluded, “may be a viable strategy to facilitate limiting excessive consumption of free sugars in an obesity-promoting environment.” Clearly, healthy sugar intake is one ingredient in the formula for more satisfying sleep. Something else that can help you get a good night’s rest? Drinking enough water. Here’s how hydration affects sleep.