List Of Vegetables Of The Tuber Family:
Beet, Potato, Carrot, Sweet Potato, Taro, Yams, Jicama, Parsnips
Tubers are roots that grow underground. Without tools and the ability to cook, humans would be hard pressed to consume them. We certainly did not evolve eating them. With the exception of potatoes, most of these could be eaten safely in a raw state, but the task would not be a pleasant one.
The fact that an uncooked sweet potato does not present much temptation to a hungry human should be reason enough to warn you away from one. Beyond that, tubers are high in starch and cellulose, and so hard for the body to digest.
Potatoes contain toxic compounds called glycoalkaloids, of which the most common are solanine and chaconine. This poison, when not lessened through cooking and peeling, can cause headaches, diarrhea, and cramps; it's meant to drive away predators, like yourself.
Tubers should generally be avoided, but some, such as carrots and jicama, are ok to include.