Butternut squashes are a variety of winter squash that belongs to the gourd family. It's considered a starchy vegetable, and like other starchy vegetables, such as corn and potatoes, it's higher in carbohydrates than non-starchy vegetables. One cup of butternut squash contains about 21 grams of carbohydrates, which is about 5% of the daily recommended intake for carbs. Butternut squash is also a good origin of fiber and vitamins A and C.