You may feel bloated initially with fiber because fiber pulls water into the gastrointestinal (Intestine) tract.
“At first, it was believed that high fiber intake reduced colon cancer. The subsequent studies turned out to be a bitter disappointment. The 1999 prospective Nurses’ Health Study followed 88,757 women over sixteen years, and found no significant benefit in reducing colon cancer risk.”
The findings of the Nurses’ Health Study, so it is narrowly correct. However, the broader claim that subsequent studies did not support the fiber-cancer link does not appear to be correct. Most (not all) meta–analyses of observational studies, which provide a less-biased overview of the research literature as a whole, report that a higher intake of fiber is associated with a small but significant reduction in colon cancer risk. Hence, it comes under the benefit of the doubt.