Vegetables contain primarily starch, however the amount in most vegetables is low since they tend have a high water content. Starchy vegetables like potatoes, peas, corn and legumes are exceptions. Jicama is a root and is generally consumed as a vegetable. It has a high water content and is low in calories with only 25 calories per half cup serving. It is also a good source of fiber, providing 3 grams per half cup.