Excess Body Fat Causes Cancer
The evidence that excess body fat increases the risk of developing cancer is much stronger now than ever before, according to a landmark report issued today by the American Institute for Cancer Research (AICR) and the World Cancer Research Fund (WCRF). Evidence linking consumption of alcohol, red meat and processed meat to increased risk is also deemed convincing.
Released today at a Washington news conference, the report -- Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective -- is the most comprehensive ever published on the evidence linking cancer risk to diet, physical activity and weight. The result of a five-year process involving nine independent teams of scientists from around the world, hundreds of peer reviewers, and 21 international experts who reviewed and analyzed over 7,000 large-scale studies, the report includes 10 recommendations for cancer prevention.
Body Fat Convincingly Linked to Six Cancers
Finding that the evidence is now convincing that carrying excess body fat increases risk for cancer of the esophagus, pancreas, colon, kidney and endometrium as well as post-menopausal breast cancer, the report recommends that people aim to stay within the healthy weight range (18.5 to 25) on the BMI chart throughout adult life. It further recommends staying as lean as possible within that range.
This recommendation is more stringent than AICR -- and most other organizations -- has previously issued on weight and reflects the stronger evidence that has emerged over the last few years.
"The recommendation reflects what the science is telling us today. Even small amounts of excess body fat, especially if carried at the waist, increase risk," Panel Member Phillip T. James, MD, DSc, said today.
Because the evidence on weight gain is now so much stronger, the new report offers two evidence-based recommendations on how to avoid excess body fat. First, the report advocates being physically active for at least 30 minutes each day. The evidence shows that physical activity produces a "double whammy" by reducing cancer risk in its own right while helping to maintain a healthy weight, which is also protective.
Second, the report calls for limiting the intake of "energy-dense foods," especially processed foods high in added sugar, or low in fiber, or high in fat.
Panel Urges Limits on Red Meat
The new assessment finds the evidence linking red meat (beef, pork and lamb) to colorectal cancer is more convincing than it was a decade ago. Accordingly, AICR's expert panel recommends limiting consumption of red meat to 18 ounces (cooked) per week. Beyond this amount, the evidence indicates, every 1.7 ounces of red meat consumed per day increases cancer risk by 15 percent.
The recommendation concerning processed meats is even more rigorous. Based on convincing evidence, the panel recommends avoiding processed meats such as bacon, ham, sausage and lunchmeat. In regard to processed meat, the evidence shows no safe level of consumption. Every 1.7 ounces of processed meat consumed per day increases risk of colorectal cancer by 21 percent.
"That's why we recommend that if people eat processed meat at all, they save it for special occasions like ham at Christmas or the occasional hot dog at a baseball game," said James.
"We are also recommending at least 5 servings of non-starchy vegetables and fruit daily because, like physical activity, they pack a double whammy against cancer. Probable evidence indicates they help reduce cancer risk on their own, and as low-energy-dense foods, they help maintain a healthy weight, which the evidence shows has a big influence on cancer risk," James said.
Alcohol Consumption Linked to Cancer
The AICR expert panel found the evidence convincing that alcoholic drinks are linked to cancers of the mouth, pharynx, larynx, esophagus, as well as colorectal cancer in men and pre-and post-menopausal cancer in women.
Recommendations for Cancer Prevention
1.Be as lean as possible within the normal range of body weight.
2.Be physically active as part of everyday life.
3.Limit consumption of energy-dense foods.