Blender Nromal Problem

I am working on my first model in Blender and encountered the famous flipped normal problem on a large scale. I have done an ugly workaround atm but was hoping that someone could explain why this occur so that I can avoid it in the future.

My character currently consists of a skeleton rig and three mesh objects. A body and two eyes. The odd thing is that the body imports to unity with the normals flipped the wrong way so that I can see into the model while the eyes are imported the correct way. I temporarily fixed this by flipping the normals in Blender so that I see through the character but it appear correctly in Unity.

This proves that either Blender or Unity is flipping the normals around without asking, I am currently betting on the later, but why?