Different indigenous peoples ate very different diets, from zero carb to mostly carb, but each group ate a smaller variety of foods because they were constrained by their geography. Most diets were high in animal fats though, and even the ones that were high in carbohydrate had adequate amounts of animal fat in the form of cheese and (raw, whole) milk.

Potatoes didn't exist in the Old World until brought from South America. Corn (maize) and tomatoes also came from the New World.