Fibers are very good for humans
Dietary fiber, also known as roughage or bulk, includes the parts of plant foods your body can't digest or absorb. Unlike other food components, such as fats, proteins or carbohydrates — which your body breaks down and absorbs — fiber isn't digested by your body. Instead, it passes relatively intact through your stomach, small intestine and colon and out of your body.
Fiber is commonly classified as soluble, which dissolves in water, or insoluble, which doesn't dissolve.