"Tryptophan is an essential amino acid and the sole precursor of serotonin production, a neurotransmitter that promotes and aids in sleep," Schapiro tells Romper. You'll hear talk about tryptophan every Thanksgiving because it's found in turkey (and it's often the excuse used for why so many people take a nap after dinner) but it's found in all foods that are high in protein. Schapiro adds that animal-derived products like turkey, beef, eggs, and salmon contain higher amounts than plant-based proteins (tofu, beans, nuts, and seeds).

"Whether you’re preparing dinner or a bedtime snack for your little one, be sure to incorporate a source of protein onto their plate. Protein will help keep your child’s belly full, making them less likely to ask for food soon before bedtime," she says. Schneberg echoes this idea, saying she personally recommends a bedtime snack that blends protein with a complex carb, like almond butter on a piece of whole grain toast or a banana paired with some almonds.

Whole grains, like brown rice, barley, quinoa, and even popcorn, are rich in fiber and B vitamins. "Fiber helps to manage blood sugar levels and prevent sugar spikes and crashes throughout the night," Schapiro tells Romper, so it's less likely your child will wake up hungry. She says that when compared to white rice, barley has a greater concentration of magnesium, calcium, and a neurotransmitter named GABA. "Low levels of GABA have been linked to shorter sleep duration and insomnia," Schapiro says. (Fun fact: studies show that doing yoga can also increase GABA, per Psychology Today, so you could try a few poses with your kid before bed).

Carbohydrates alone do not contain tryptophan, but eating "whole grain crackers or a teaspoon of honey before bed can slightly increase insulin levels, which can speed up tryptophan transport to your child’s brain," Schapiro says.

You've probably heard of melatonin and maybe there's even a bottle of it in your medicine cabinet, but did you know melatonin is also found in certain foods? Almonds, oats, and cherries "contain natural sources of melatonin, a hormone notoriously known for controlling sleep-wake cycles and promoting a good night’s sleep. Other rich sources of melatonin can be found in cow’s milk and human milk, mushrooms, cereals, legumes, and seeds," Schapiro says.

This may be how the idea of warm milk before bed as a sleep tool became popularized. When I asked Schapiro about whether there was any truth to this wives' tale, she said there are many convincing theories on why this could be true, none of which are confirmed with ample research. Part of it may be psychological; warm beverages are comforting. Another idea is that the nutritional composition of milk supports sound sleep. "Milk is high in tryptophan, calcium, and Vitamin D. As mentioned earlier, calcium and Vitamin D may play a role in sleep quality. Tryptophan increases serotonin levels, which increases melatonin or the 'sleep-inducing' hormone," Schapiro tells Romper. So even if it's not totally understood why milk aids in sleep, it's definitely worth a try.

Okay, so fatty fish like tuna and salmon may not be high on your child's list of favorite foods, but if they do like it, having fish for dinner may actually help your kid sleep a bit better. "Fatty fish contains high amounts of Vitamin D, which has been associated with a longer and better sleep," Schapiro says. It's also just really all-around healthy and is a rich source of omega-3’s and monounsaturated fats. "These 'heart-healthy' fats decrease inflammation in the body and may protect your child from chronic illnesses," Schapiro says.

I covered milk briefly already, but as it turns out, all dairy can lead to healthy snoozing. "Milk, yogurt, and cheese contain an adequate source of protein, calcium and potassium. Calcium and potassium are essential for building strong bones in growing children, and deficiencies in these two nutrients have been associated with impaired sleep," Schapiro says. And if your kid isn't super into dairy, Schapiro adds that bananas are also a good source of potassium.

Admittedly, when you're trying to get through a bedtime routine Brazil nuts may not be top of mind, but maybe they should be. "Brazil nuts are packed with selenium, zinc, magnesium, and tryptophan. Studies found that lower levels of these nutrients were related to insomnia and depressive symptoms," Schapiro says. Low levels of magnesium can increase cortisol levels, which increases psychological stress and may interrupt sleep, Schapiro says. Depending on their age, The Recommended Dietary Allowance (RDA) for magnesium in children is 80 mg-240 mg. Some rich sources of magnesium include pumpkin seeds, almonds, spinach, peanut butter, and black beans, Schapiro tells Romper. Just remember to be careful with giving your toddler whole nuts.

Just because your child isn't guzzling coffee (let's hope), you may be surprised that they may still be consuming some amount of caffeine (Schapiro says that 75% of children consume caffeine every day). "Tea, coffee, soda, energy drinks and dark chocolate are the main culprits," Schneeberg tells Romper. You'll also want to be mindful of too much refined sugar, but that doesn't mean you have to be completely anti-dessert; instead try to be aware of how close to bedtime they're having these treats. "Baked goods and candies that are high in sugar, refined carbohydrates, and saturated fat should also be avoided before bedtime. These overly processed, sugary foods can lead to a 'sugar-rush,' leaving your child energized and unable to wind down," Schapiro says.