Answer:
You throw away my outside, you cook my inside. Then you eat my outside and you throw away my inside. What am I?
I am a celebrity fish.
Many people own a copy of me. Without me the world would fall.
I am the minerals vital for your good health.
I start with an E end with an E and have a letter in me.
No matter how little or how much you use me, you change me every month.