Wired Instead of Tired? This Common Food May Be Keeping You Up

Back in my marathon training days, I noticed something interesting: if I ate something sugary before a run, I had a hard time keeping my heart rate down.

More recently, my Oura ring has noted the same pattern. My heart rate stays elevated late into the night when I've had a sweet treat post-dinner.

We know that Americans eat too much added sugar (about 17 teaspoons of sugar each day!), leading to higher risks of heart disease and type 2 diabetes.

We're learning that the issue isn't just how much, but when.

Not all sugar is a problem.

Naturally occurring sugars, found in fruit or dairy, come packaged with fiber, protein, vitamins, and minerals.

Added sugars, found in refined, ultra-processed foods like candy, cookies, and baked goods, are strongly linked to health issues—including poor sleep.

When you eat something high in added sugar, your blood sugar rises quickly, and your body releases insulin to move that sugar into your cells.

That’s a normal process. The issue is how fast it happens and what comes afterward.

A sharp spike in blood sugar, especially late in the day, is often followed by a rapid drop. Your body may respond to that drop by releasing stress hormones like cortisol and adrenaline to bring levels back up.

Those hormones are great if you’re trying to outrun danger. Not so great when you’re trying to fall asleep.

Cortisol is supposed to be low at night, while melatonin, the hormone that signals sleep, rises. When cortisol stays elevated, melatonin gets delayed.

​You feel wired when you want to be tired.​

Blood sugar swings affect sleep quality, not just falling asleep.

Diets high in added sugar are associated with shorter sleep duration, more nighttime awakenings, and disruptions in deep and REM sleep—the stages that affect memory, learning, and emotional regulation.

That’s why a late-night sugar hit can leave you feeling groggy and unrested the next day, even if you got “enough” hours.

Should there be a sugar curfew?

There's no magic time, but our metabolism follows a circadian rhythm.

As the evening goes on, digestion slows and insulin sensitivity decreases, meaning your body doesn’t handle sugar as efficiently.

Eating your last meal or substantial snack 2-3 hours before bed gives your body time to digest and keeps blood sugar steadier as sleep hormones rise.

If a nighttime dessert consistently leaves you restless or waking overnight, that’s useful feedback from your body.

Going to bed hungry can also disrupt sleep.

If you’re genuinely hungry before bed, skipping food entirely isn’t the answer.

A small snack that includes protein, fiber, healthy fats, and complex carbohydrates is the best choice.

This combination slows digestion, preventing blood sugar spikes that impact your sleep

Try Greek yogurt with berries and nuts, chia seed pudding made with milk or fortified nondairy milk, or cottage cheese with a little fruit. Tart cherries are a good choice. They’re naturally sweet and have been linked to improved sleep quality.

The takeaway isn’t “don't eat dessert.”

It’s what and when you eat that matters.

Pair foods thoughtfully, favor naturally occurring sugars when possible, and notice how your body responds.

A great night's sleep is worth a little awareness and planning!