Maintaining a healthy weight—and making other smart lifestyle choices, like including limiting processed meat and alcohol—can reduce a person’s cancer risk by up to 40%, according to a new report by the non-profit World Cancer Research Fund (WCRF).
The WCRF updates its recommendations for cancer prevention once every 10 years. The new guidelines, which will be presented this week at the European Congress on Obesity in Vienna, are based on a review of data from 51 million people, including 3.5 million cancer cases.
The findings from this latest review are mostly consistent with previous analyses done in 1997 and 2007. But the new guidelines offer the clearest and most up-to-date picture of which lifestyle factors influence cancer development, says Elisa Bandera, MD, a member of the panel that compiled and wrote the report. They also offer 10 concrete ways people can reduce their own personal risk.
“This is confirmation of what we already knew,” says Dr. Bandera. “And that’s important, because it involves this very thorough approach, looking at every possible point of evidence and the best quality data we have.” About one in six deaths annually worldwide are currently due to cancer, and the number of cases is expected to increase 58% by 2035, as more countries adopt “Western” lifestyles.
While the previous WCRF report found a causal relationship between being overweight or obese and seven cancers, the new report increases that number to at least 12: liver, ovarian, advanced prostate, stomach, mouth and throat, colorectal, post-menopausal breast, gallbladder, kidney, esophageal, pancreatic, and uterine cancers. WCRF isn't the only group that's made a connection between obesity and cancer, either. A 2016 report by another non-profit, the International Agency for Research on Cancer, linked excess weight to 13 types of cancer.
To reduce your personal risk of cancer, the WCRF recommends the following 10 steps:
Maintain a healthy weightWalk more and sit lessEat more whole grains, vegetables, fruits, and beansAvoid high-calorie foodsLimit consumption of red and processed meatsLimit consumption of sugar-sweetened drinksDon’t drink alcoholDon’t rely on supplements to protect against cancerBreastfeed your baby for six monthsContinue to follow the agency’s recommendations after a cancer diagnosis
Some of these recommendations, like skipping , will protect against cancer because they help prevent weight gain. Others, like being physically active, have also been shown to have a protective effect of their own, independent of weight control.
Limiting alcohol is a big one, say the report’s authors, because drinking is strongly linked to an increased risk of six different cancers. For example, in recent years, even low to moderate consumption of alcohol has been shown to raise the risk of breast cancer.
Reducing red and intake is another important thing people can do to reduce their cancer risk, the report states. The researchers recommend eating no more than three portions a week of beef, pork, and lamb. They also recommend eating “very little, if any, processed meat”—including bacon, sausage, and cured lunch meats—because it’s high in fat and salt, and because it’s been shown to cause bowel cancer.
The report also discourages the use of vitamins and supplements for cancer prevention. “Some types of supplements—like prenatal vitamins—are very important,” says Dr. Bandera. “But some are being marketed as cancer preventives, and there’s no evidence that any supplements really work that way.”
In some cases, she says, supplements could even be harmful for people who have already been diagnosed with cancer. “They’re taking something that they think will help, but actually it could interrupt their treatment,” she says.
When people follow all 10 of these guidelines, Dr. Bandera says, it’s estimated that they can reduce their cancer risk by about 40%. But that doesn’t mean it has to be all or nothing.
“Even doing a little bit is better than nothing,” she says. “Especially for something like physical activity, it can be difficult to find an hour a day to exercise. It’s important for people to know that if you cannot do a whole hour, doing 10 minutes here and 10 minutes there can also be helpful. You have to start somewhere.”
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Some news outlets have seized on the red meat and alcohol items on the WCRF's list, with headlines about how cutting out “bacon and booze” can slash your cancer risk. Those are both important, says Dr. Bandera, but she also stresses that the best approach is a multi-faceted one.
“We want to promote a set of holistic lifestyle factors, rather than just focusing on one nutrient or one food,” she says. Overall, she adds, it’s healthy patterns of diet and physical activity that will really help lower cancer rates around the world.