The main ingredient in a smoothie is typically fruit. Common fruits used in smoothies include bananas, berries, mangoes, and spinach, among others. The fruit provides natural sweetness, flavor, and a variety of essential nutrients, such as vitamins, minerals, and antioxidants. Smoothies can also incorporate other ingredients like yogurt, milk, or juice, to create a creamy texture. Additionally, many people add vegetables, protein powders, or superfoods to enhance the nutritional value. Smoothies are popular for breakfast or as a healthy snack, providing a refreshing and convenient way to consume a variety of nutrients in a single serving.