Here’s a great video by Dr. Greger, reviewing some crucial science:
The American Institute of Cancer Research teamed up with the UN Food and Agriculture Organization (FAO) and World Health Organization (WHO) to employ many top scientists from around the world. They reviewed the extensive literature on cancer and prevention and they then came up with a consensus statement about how to prevent cancer.
They then took it one step further. They looked at large database and tested whether adherence to their recommendations resulted in less cancer. In fact, cancer was dramatically lower in people who adhered to the recs, as was heart disease.