Absolutely do not leave anything sugary or sweet out. The ants will be all over it within minutes. My first night I ate a bowl of cereal and left the box of cereal out. By the morning, there were thousands of ants all in the box and covering the bowl that I ate out of. It was so bad that I had to throw the entire box of cereal away and whip the ants off the counter. If you are going to eat anything sugary, finish it. Do not risk leaving it out and having ants all over the place.