Quinoa is technically a seed - considered a pseudo-cereal grain - that contains a whopping eight grams of protein per serving. It's a complete protein, containing all nine essential amino acids, something rarely found in plant-based food. And if that wasn't enough, quinoa is high in fiber, rich in vitamins and minerals, and gluten-free. This makes the superfood an ideal ingredient for those eating vegetarian, vegan, and/or gluten-free.