There is convincing evidence that both red meat and processed meat are causes of colorectal cancer.
This is why AICR recommends limiting intake of red meat-- that means beef, lamb and pork -- to no more than 18 ounces (cooked weight) a week.
We also recommend avoiding processed meat, which is any meat that has been preserved by curing, salting or smoking, or by adding chemical preservatives. This includes hot dogs, ham, bacon and sausages.
There is convincing evidence that carrying large amounts of excess body fat particularly around the stomach is a cause of colorectal cancer. This is one of the reasons AICR recommends staying as lean as possible within the healthy weight range.
The evidence that alcoholic drinks are a cause of coloretal cancer is convincing in men and probable in women. This is one reason AICR recommends limiting alcoholic drinks to no more than two a day for a man and one for a woman. (Another reason for the difference: Evidence linking alcoholic drinks to breast cancer is very strong.)
Finally, the evidence that regular physical activity reduces colorectal cancer risk is also convincing, which is one of the reasons we recommend being physically active every day in any way for at least half an hour.
AICR experts estimate that following the above advice could prevent an astonishing forty-five percent of colorectal cancers in the US every year.
That's over 48,000 cases every year.
strong, consistent and unlikely to change in the future
compelling but not quite strong or consistent enough to be "convincing"
Limited Evidence – Suggestive
too limited for a grade of "probable", but a general consistency in the data
Limited Evidence – No Conclusion
too inconsistent or insufficient for a definitive grade
Substantial Effect on Risk Unlikely
enough evidence to rule out a connection