Like others have said, those fan leaves are like Solar Panels, absorbing light just like your body does when you are in the sun. Think about how we humans absorb vitamin D from the Sun, and how light is important when it is transferred through the right "Channels". You'll see those big leaves attached to the base of a branch, where nutrients are transferred into and up the branch. This is vital for proper health, allowing sugars and energy to fill your buds with joy! If you hack away, you will find your harvest (yeild) and potency most likely affected. I did so much research on this, my head was spinning and I found that changing the natural function of ANY plant can have dire consequences. This is my motto; "Move and Tuck". If the leaves are showing signs of dying or the lack of light has caused them to wither, then consider kissing them goodbye, otherwise I would leave the plant alone.