A third of cancers are caused by diet and lack of exercise and could be prevented, states a report that urges people to stay slim and abstain from too much fast food, red meat and preserved meat, such as ham and bacon, and alcohol.
The report from the World Cancer Research Fund, which had input from more than 200 scientists and took five years to produce, is the most authoritative overview of the role that food, drink, obesity and exercise play in causing cancer. It concludes that lifestyle changes could play almost as big a role as stopping smoking in preserving us from disease and that being fat is a big cancer risk. Top of the 10 recommendations for a healthier life in the report is that people should keep their weight down throughout their life.
”The most striking thing to emerge from the report is the importance of overweight and obesity,” said Michael Marmot, professor of epidemiology and public health at University College London and chairperson of the panel that reviewed 7 000 studies on causes of cancer.
Obesity is normally measured by body mass index (BMI), a person’s weight in kilograms divided by height in metres squared. A BMI above 30 is considered obese, while 25-29 is overweight. The World Cancer Research Fund recommends a BMI at the lower end of the healthy range, between 18,5 and 25.
Excess body fat is not only a trigger for endometrial cancer, but also oesophagal, pancreatic, bowel, post-menopausal breast and kidney cancers, states the report. Fat around the abdomen is linked to bowel cancer. ”Young adults should try not to put on weight throughout their adult life,” said Marmot.
The report has similarly robust recommendations on alcohol, exercise and meat consumption. Everyone should have at least half an hour of exercise a day — but the panel says it should be vigorous, not moderate exercise. Moderate exercise should last for an hour a day. The third recommendation is to avoid energy-dense foods, which include fast foods high in fat and sugar.
Eating mostly plant-based foods, such as fruit and vegetables, reduces cancer risk and too much red meat raises it. The panel recommends no more than 500g a week. Processed meat — such as the ham and bacon with added preservatives sold in supermarkets — should be avoided altogether, it says, because they raise the cancer risk by about 10%.
Marmot said: ”This is a very positive message. What we’re saying is that perhaps a third of cancers are diet-related. Cancer is largely preventable.” — Â