Only one in two Americans is aware that obesity can raise the risk of cancer. And fewer than half understand that alcohol, inactivity, processed meat, eating lots of red meat and low consumption of fruits and vegetables are linked to cancer risk, the researchers said.

“There is a clear crisis in cancer prevention awareness,” said Alice Bender, head of nutrition programs at the American Institute for Cancer Research.

A larger percentage of Americans mistakenly believe that stress, fatty diets and other unproven factors are linked with cancer, according to the institute’s 2017 Cancer Risk Awareness Survey.

“It’s troubling that people don’t recognize alcohol and processed meats increase cancer risk,” Bender said in an institute news release. “This suggests the established factors that do affect cancer risk are getting muddled with headlines where the research is unclear or inconclusive.”

Factors Affecting the Risk of Cancer

Highlights of the survey findings include:

• Fewer than 40 percent of Americans know that alcohol affects cancer risk.
• Only 40 percent know that processed meats are also associated with cancer risk.
• Fifty percent of Americans are aware that being overweight spurs cancer risk, up from 35 percent in 2001.

Nearly one-third of common cancers in the United States could be prevented through diet, weight management and physical activity. That increases to half when factors such as not smoking and avoiding sun damage are added, according to the institute.

Research has linked alcohol to at least six cancers, including colon, breast, liver and esophageal. Studies have also shown that bacon, hot dogs and other processed meats may raise the risk of colon and stomach cancers.

Only half of Americans know that obesity increases the risk of several cancers and that a healthy weight is the second most important way — after not smoking — to reduce cancer risk, the researchers said.

“We know a lot of healthy people do get cancer and sometimes it’s easier to worry about genes or uncontrollable things rather than your everyday choices,” said Bender. “But the research says that being physically active, staying a healthy weight, and eating a plant-based diet has the potential to prevent hundreds of thousands of cancer cases each year,” Bender aded. “It’s a powerful message.”