Soda pop
Soda contains a series of ingredients that would potentially cause cancer, even though the link has not been properly established. For example, it contains added sugar and contributes to obesity, which is associated with cancer. It has aspartame, saccharin, and other additives proven as carcinogens in animal models. Even though they might not have the same effect in humans, they do alter your gut microbiota and trigger certain effects that you might want to avoid.