Carbohydrates are typically the most abundant component of food and the most misunderstood. While most often equated with starch, there are many different types depending on their compositions and molecular lengths. Short chains are often simple sugars, while long chains can be starch or fiber. We will discuss the structural variations of carbohydrates and how these variations lead to different biological functions. We will also discuss the differences between starch and fiber and how one gives us nutrition while the other feeds our microbiome.