Pasta, white bread, sugary candy and baked goods: Americans love them, but could all those “refined” carbohydrates and sugars be keeping people up at night?

About 30% of Americans have insomnia, and a new study finds carb-heavy diets may share part of the blame. The study looked at diet-linked fluctuations in blood sugar, said lead author James Gangwisch. He is assistant professor of clinical psychiatric social work at Columbia University in New York City.

“Highly refined sugars” — added sugars, sodas, white rice, refined wheat flour — have what’s known as a high glycemic index, which can trigger a sudden rise in blood sugar. “When blood sugar is raised quickly, your body reacts by releasing insulin, and the resulting drop in blood sugar can lead to the release of hormones such as adrenaline and cortisol, which can interfere with sleep,” Gangwisch explained in a university news release.