When I was a teenager, a myth existed that if you ate too much lemon, it would cause you leukaemia. However, nowadays, more and more people claim that lemon is an excellent chemotherapeutic food.
On another note, as for the white sugar, I must say that when we were children and ate it, I believe that our parents could not imagine how addictive and harmful it could be for our health. Today, there are researches that prove how dangerous it is for our body.