What is it exactly that make those greens we add to our smoothies so beneficial? Leafy greens are low in calories, packed with vitamins, and are needed for clear skin and healthy immune systems. Greens such as spinach and kale contain more potasium than bananas and can help reduce blood pressure. Leafy greens keep you feeling full longer which will help you avoid unnecessary snacking. Get on our week long green smoothie program and thank us later.