The number 1 cancer-fighting food is not a specific food, but rather a group of plant-based foods that contain phytochemicals. These foods include berries, broccoli, tomatoes, walnuts, grapes, and other vegetables, fruits, and nuts . Research has shown that a diet filled with a variety of vegetables, fruits, whole grains, beans, and other plant foods helps lower the risk of many cancers . Phytochemicals, which are found in plant-based foods, have been shown to have anti-cancer effects in laboratory studies . Therefore, consuming a diet rich in plant-based foods that contain phytochemicals may help reduce the risk of cancer.