The American National Cancer Institute has spent over $20million on a research campaign to determine the most cancer protective foods that we can include in our daily diets. This is what it came up with:

Diets that are based on plant foods, including lots of vegetables, fruit, wholegrains and legumes, are linked to lower rates of cancer. All vegetarian diets (including those which are vegan, include eggs, or include meat or fish up to once a week) are associated with overall lower rates of cancer.