Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Diverticular Disease ?
    ### Response:
    Fiber is a substance in foods that comes from plants. Fiber helps soften stool so it moves smoothly through the colon and is easier to pass. Soluble fiber dissolves in water and is found in beans, fruit, and oat products. Insoluble fiber does not dissolve in water and is found in whole-grain products and vegetables.
    