I have read that cutting carbs is unhealthy, but all my friends are losing weight by doing it

it is unhealthy, if you cut them out completely. your body needs carbs - good carbs - complex carbs (whole grains, veggies... ), but not simple carbs (white bread, french fries ... ). Carbs are one of the primary source of energy and you shouldn't cut them off completely - however if you do follow traditional western diet you do probably eat them too much, so , yous, you should limit them.