There are a lot of variables when it comes to getting kids to sleep through the night. Some, like getting ample naps during the day, are relatively easy to address. Others, like teaching them to self-soothe, are a bit trickier. Then there is one of the less-discussed factors that can make or break a child’s sleep quality: nutrition. The foods that kids eat — not just before bed, but all day long — can have a significant impact on how easily they drift off at night. Here are a few ways nutrition can affect sleep, and foods to help sleep.

Caffeine Comes in Many Forms

You probably know that alcohol and caffeine do not good bedfellows make. But wait, you say, my kid isn’t boozing or pounding Red Bulls? We’ll take your word on the Jack Daniels, but the odds are your child is still getting more caffeine than you realize. “It’s not only in coffee and tea,” says Kristen Knutson, Ph.D., assistant professor of medicine and a member of the Sleep, Metabolism and Health Center at the University of Chicago. Do you treat your child to chocolate ice cream? There’s caffeine in there. Does he eat granola or protein bars? Yup, caffeine. Does she enjoy the occasional Milky Way or M&Ms? Yes, it’s in there, too.

Skip the Chips

Eating fatty foods before bed can negatively impact sleep quality, according to a study in the Journal of Clinical Sleep Medicine. Steer clear of chips or cookies and offer your child a cracker or small piece of fruit for a bedtime treat.

Avoid Cortisol Triggers

Cortisol is a stress hormone (part of that whole fight-or-flight thing), but it plays a lot of other important roles in the body, such as controlling energy production, building muscle strength, and resisting infections. Cortisol levels rise and fall over the course of a 24-hour period, and if they are elevated at night it makes it difficult to sleep. The nutrition connection: Foods that rank high on the so-called glycemic index (mainly, sugary foods and refined starches) cause cortisol levels to rise, according to the American Nutrition Association.

Go Low-Glycemic

As opposed to high-glycemic foods, those that rate a lower glycemic score help moderate cortisol levels, supporting sound sleep at night. Load your child up on vegetables, fish, poultry, and eggs, and swap white bread for whole wheat.

Avoid Big Meals Before Bed

Worried that an empty stomach might cause their child to wake during the night, some parents serve dinner right before bed. But the stomach needs several hours to digest a large meal; consuming it too close to sleep time means the body will remain active when what you want is for it to relax. Plus, hunger-related waking in kids is unlikely, says Knutson: “For 4-year-olds and older, I wouldn’t worry about it, as long as they ate a reasonable amount during the day.”

Space Food Out During the Day

While a big dinner right before bed can backfire, missing a meal during the day or going for more than 5 hours between daytime eating can also cause sleep troubles at night. That’s because the body’s cortisol levels will rise and stay elevated if too long passes between bouts of energy intake. Make sure your child has access to a supply of healthy snacks, whether it’s carrot sticks in his school backpack or unsweetened applesauce cups at daycare.

Obesity and Sleep

While good nutrition promotes healthy sleep, poor sleep is associated with an increased risk for obesity in kids, according to a study in the journal Pediatrics. Avoid this downward spiral by feeding your child healthy, whole foods at regular intervals during the day, and sticking to a consistent sleep schedule at night.