Twenty percent of U.S. adults get just five hours of sleep, or less, every night, according to a recent Gallup poll.

Experts agree you should prioritize getting enough sleep if you want to wake up feeling energized the next day. But there are also some foods that nutritionists say can boost your energy if you do need a pick-me-up.

These are the four types of foods that are the key to more energy, according to experts.

4 energy-boosting foods, according to nutritionists

1. Complex carbohydrates

Simple carbohydrates, including white bread, quickly break down into sugar and instantly lead to spikes in your blood sugar, Dr. Nancy Rahnama, an internist and clinical nutritionist, told CNBC Make It in January of 2023.

"And anything that spikes is going to crash," Rahnama said. "This high-end crash and burn throughout the day leads to fatigue, irritability, changes in the mood, headaches, hunger [and] cravings."

Complex carbohydrates, unlike simple carbs, are "digested more slowly and supply a slower release of glucose into the bloodstream," according to the American Heart Association.

Having complex carbs for breakfast can help you feel energized throughout the day, registered dietitian Maya Feller told CNBC Make It last year.

The complex carbohydrates that Feller and other experts suggest eating for more energy are:

• Wheat bread
• Sweet potatoes
• Oatmeal
• Pumpkin seeds
• Apples
• Chickpeas

2. Fiber-rich foods

We can all use more fiber in our diet. A recent study shows that most Americans aren't getting enough.

It turns out that eating foods high in fiber at the very top of your day can be a great hack for more energy, according to Rahnama.

Here are a few fiber-rich foods that nutritionists recommend:

• Berries
• Quinoa
• Prunes
• Leafy greens, especially spinach

To incorporate these foods in your meals, you can enjoy a mix of berries and prunes in a smoothie or eat a leafy green salad with quinoa.

3. Heart-healthy fats

A common food group that nutritionists say can serve as a great energy-booster is heart-healthy fats.

Foods high in Omega-3 fatty acids support brain health, and fatty fish like salmon and sardines can boost mood and lower levels of depression, Patricia Bannan, a dietitian and nutritionist, told CNBC Make It in 2022.

Depression can reduce your energy levels and interfere with your ability to be productive.

Bannan also noted that unsaturated fats "may help keep inflammation at bay and reduce blood pressure, which are important for brain health."

Heart-healthy fats that you can consider are:

• Avocados
• Tofu
• Olives
• Sardines
• Dark chocolate
• Salmon

4. Water

This one may seem simple, but it can often be overlooked as a way to increase your energy. Feeling dehydrated can affect your mood and cause you to feel sluggish, according to the Centers for Disease Control and Prevention.

On the other hand, getting enough water throughout the day can help to "maintain energy levels by keeping our muscles energized," said Lauren Manaker, a registered dietitian nutritionist, in an article she wrote for CNBC Make It.

The jury is still out on exactly how much water you should drink each day, especially considering different factors like the amount of physical activity you're engaging in. But it doesn't hurt to reach for a glass of water when you're feeling tired and could use a boost of energy.

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