Tests on subjects who swapped a fatty, meat-heavy diet for foods rich in beans and vegetables found a drop in biological markers for cancer in just two weeks. … On the rural African high-fibre diet, gut microbes produced more butyrate, a chemical that has anti-cancer properties. Meanwhile, on the high-fat western diet, the microbes produced more bile acids, which may increase cancer risk. Research has shown before that high-fibre diets are linked to reduced colon …