Don't listen to this guy ^^^

NEVER remove fan leaves from a cannabis plant unless they are ready to fall off on their own. They don't 'just suck up water'; they MAKE SUGARS! They are where the bulk of photosynthesis on the plant occurs, where the plant takes the energy from the sun and uses it to bind carbon from the air and hydrogen from the water into the basis for all the yummy resins it is going to make!

It's like cutting the blades off a wind turbine to 'make it spin faster'...