Red and processed meat. Avoid the hot dog and sausage during lunch time and just don't be tempted by the hot dog vendor. Studies have found a strong connection between colon cancer and processed meat such as hot dogs and cold cuts, as well as beef, pork and lamb. The stats are pretty convincing: Women who ate approximately 1 ounce of processed meat (about one slice of bologna) two or three times a week for a decade were 50 percent more likely to develop colon cancer; eating only 2 ounces of red meat a day long-term can increase the odds of rectal cancer by as much as 40 percent, according to a large study in The Journal of the American Medical Association. Colon cancer isn't a carnivores-only concern. Women who downed 1.5 servings of meat a day had nearly twice the breast cancer risk of those who ate fewer than three servings per week, according to a study in the Archives of Internal Medicine. One possible reason? Carcinogens are created when meat is cooked at high temperatures as well as when it's processed with substances such as nitrates.

How much to eat. Think of meat as a side dish, Kushi says. Stick to less than 3 ounces of red meat a day, and avoid charring as much as possible.