Which soy beans pinto or peanuts has the most protein per cup?

Neither soybeans, pintos, nor peanuts are considered soy beans. Soy beans are a different type of legume. Soybeans have the highest protein content per cup compared to pintos and peanuts. According to the USDA, a cup of cooked soybeans provides about 29 grams of protein, while a cup of cooked pintos provides about 15 grams of protein and a cup of roasted peanuts provides about 26 grams of protein.