Prevention of colorectal cancer can be classified into three groups: primary prevention aims to prevent disease onset through a healthy diet, avoiding tobacco/alcohol, and supplementation. Secondary prevention uses regular check-ups and screening/imaging to enable early diagnosis and treatment. Tertiary prevention focuses on rehabilitation after illness. A diet high in red/processed meat, refined grains and sugars increases risk, while replacing these with poultry, fish, plants, unsaturated fats, and fiber can help prevent colorectal cancer. Other preventive measures include avoiding smoking, limiting alcohol, maintaining a healthy weight and activity levels, and taking supplements like vitamins, calcium, and magnesium.