Do you regularly reach for a candy bar to get through your classes or studies? You’re on to something. “Simply eating a snack or small meal that provides a combination of carbs, protein and fats helps the brain function,” explains Academy of Nutrition and Dietetics Spokesperson Jen McDaniel, MS, RDN, CSSD, LDN.

Unfortunately, choosing the wrong snacks can put you on a sugar roller coaster and make it harder for you to learn and stay focused. “Avoid eating highly processed carbs by themselves. For example, a sugary donut might give you a quick burst of brain-boosting glucose, but it will be quickly processed and leave you in a low blood sugar slump,” says McDaniel. Can’t help it? McDaniel says pairing a processed grain, such as a plain bagel, with something sustaining like nut butter and a hard-boiled egg, can even out the sugar surge.

How often you eat—and how much you chow down—can also affect your ability to learn. “It helps to eat every three to four hours to avoid a drop in blood glucose, which leads to physical and mental fatigue,” explains McDaniel. “In addition, aim to avoid eating large meals. Overeating can easily lead to a food coma, resulting in the desire to lie-down, not learn.”

Your best option? Don’t just grab any food for energy. Consider pre-packing a few of the following healthful snacks to get through your studies or classes.

Good for Your Brain Snacks

Tuna

Walnuts/seeds

Fresh berries

Chocolate (1/3 oz)

Oatmeal

Salad with dark veggies