Complex sentence: Sayer has, since the procedure, changed his dietary lifestyle and avoids alcohol, caffeine and foods containing spicy ingredients--another reason being that both of Sayer's parents had died of cancer-his mother of bowel cancer and his father of lung cancer.
Split into simpler sentences: Sayer has, since the procedure, changed his dietary lifestyle and avoids alcohol, caffeine and foods containing spicy ingredients. Another reason being that both of Sayer's parents had died of cancer-his mother of bowel cancer and his father of lung cancer.