A front-page article in the November 13 New York Times downplayed the role of body fat, diet and physical activity in cancer prevention by suggesting that the scientific jury is still out. Is it?

The article in question, “Medicines to Deter Some Cancer Not Taken,” endeavored to describe the current state of cancer prevention research. The article focused on results from trials with pharmaceuticals like finasteride and various dietary supplements. But the article has sparked controversy for its handling of the role of diet, physical activity and weight.

A typical paragraph: “As for obesity, researchers differ. Studies that observed large numbers of people often found that fatter people have more cancer. But many of the correlations are weak, and different studies have pointed to different cancers, raising questions about whether some of the effects are real.”

Cancer experts have taken issue with the way the article characterized the evidence on the role of lifestyle in lowering cancer risk. In online responses to the article, the author has been accused of “cherry-picking” studies and the ignoring the weight of clear and overwhelming evidence on diet, weight, physical activity and cancer.

AICR’s Take:

The effect that lifestyle in general and excess body fat in particular exerts upon cancer risk is not, as the article suggests, in serious scientific dispute.

In fact, by dismissing the convincing evidence that diet, weight and physical activity play an important role in cancer prevention in the space of a few paragraphs, the New York Times article fails to provide readers with an accurate picture of current scientific thinking. This is a disservice to readers who stand to benefit from the kind of simple everyday changes that can lower cancer risk.

The National Cancer Institute, the Centers for Disease Control and Prevention, the USDA Center for Nutrition Policy and Promotion, the American Cancer Society, the Mayo Clinic, The MD Anderson Cancer Center, The Memorial Sloan-Kettering Cancer Center, The Susan G. Komen Foundation, The Obesity Society, The World Health Organization, and many other national and international organizations agree that that an individual’s diet, physical activity and weight influence his or her chances of getting cancer.

In the landmark report, Food, Nutrition, Physical Activity and the Prevention of Cancer: A Global Perspective, published by the American Institute for Cancer Research and the World Cancer Research Fund, an international panel of experts researchers, clinicians and policy makers reviewed evidence from thousands of studies in a systematic, transparent and comprehensive fashion. This evidence was independently compiled at research centers throughout the world, using a single, rigorous set of criteria.

The panel judged the assembled evidence and their conclusions ten Recommendations for Cancer Prevention [link] have been accepted by the international medical and scientific community and are helping to shape prevention policy around the globe. The fact that this massive report, a seminal text in the field of cancer prevention, was not cited in an article that endeavors to lay out the state of prevention science is puzzling.

The judgment that excess body fat is a convincing cause of six different cancers (esophageal, pancreatic, colorectal, renal, endometrial and breast (post-menopausal)) was a key finding of the AICR/WCRF expert report. The panel’s recommendation on body fatness reads:

“Be as lean as possible within the normal range of body weight.”

The article correctly states that there are to date little data suggesting that losing weight will significantly reduce cancer risk. However, by failing to mention the clear and convincing evidence that carrying excess body fat increases cancer risk, the article fails to inform its readers about one of the most significant findings in the study of cancer prevention.

The article selectively quotes from cancer researchers, leaving readers with the impression that diet, weight and physical activity have no effect on cancer risk. This is simply not the case: In fact, in the companion AICR/WCRF report Policy and Action for Cancer Prevention, the panel estimated that approximately 1/3 of the most common cancers could be prevented through healthy diet, regular physical activity and weight management. (For specific cancers this preventability estimate is considerably higher: Esophagus, 69%; colorectum, 49%, etc.)

There are no guarantees, when it comes to cancer. Individuals with lifelong healthy habits can and do get the disease. But the science is clear: by making small, everyday choices about what eat, how much we move and how much we weigh, we can lower our risk. That’s an important and empowering message.

AICR/WCRF is an organization dedicated to funding cancer research, interpreting the global scientific literature, and educating the public about the results. We are dismayed to see science reporting that so casually dismisses what the overwhelming weight of evidence clearly shows.

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The American Institute for Cancer Research (AICR) is the cancer charity that fosters research on the relationship of nutrition, physical activity and weight management to cancer risk, interprets the scientific literature and educates the public about the results. It has contributed more than $91 million for innovative research conducted at universities, hospitals and research centers across the country. AICR has published two landmark reports that interpret the accumulated research in the field, and is committed to a process of continuous review. AICR also provides a wide range of educational programs to help millions of Americans learn to make dietary changes for lower cancer risk. Its award-winning New American Plate program is presented in brochures, seminars and on its website, www.aicr.org. AICR is a member of the World Cancer Research Fund International.