The importance of choosing healthy and nutritious snacks is great, although my non-nutirion expert self can't put exact number on it. I try to make and consume food that is not super processed and is also rich in nutrients and protein. Spinach is one of those good, go to foods, but unfortunately for me, I hate the taste. Over time, I have found ways to add spinach to meals while masking the taste. One consistent and easy way I have done this is with smoothies.
That being said, here is a Knowmia Lesson on how to make a DELICIOUS GREEN SMOOTHIE. It's very easy to follow and requires little work. Below is the Knowmia Lesson, but I have imported it to YouTube for easy viewing.