Cookies originated in Persia in the 7th century AD and spread throughout Europe in the Middle Ages. They were first brought to America by English, Dutch, and Scottish immigrants and became popularized through early American cookbooks. There are hundreds of cookie varieties that developed based on geographic and cultural influences. Cookies undergo chemical reactions when baked such as proteins unfolding and sugars caramelizing to develop texture, color, and flavor. While cookies can increase calorie, blood sugar, and cholesterol levels if eaten in excess, using healthy oils and ingredients can minimize negative health effects.