Higher adherence to unhealthful plant-based diets is not significantly associated with colorectal cancer risk, despite a trend toward increased risk, suggesting that poor-quality plant foods may not independently elevate colorectal cancer risk as strongly as they do for breast cancer.

Eating whole plants like vegetables, fruits, and whole grains feeds good gut bacteria that make compounds to strengthen the colon lining and calm inflammation. This stops cancer from starting. Eating refined carbs and sugary plant foods does not do this, and even though they cause metabolic stress, the colon does not respond with more cancer because the protective mechanisms from fiber and plant chemicals are missing, not because the harmful ones are strong enough to cause cancer on their own.