New Zealand's barbecue culture faces a challenge with warnings of the danger of eating too much red meat. Photo / Peter Meecham

New Zealand's barbecue culture faces a challenge with warnings of the danger of eating too much red meat. Photo / Peter Meecham

Want the best shot at avoiding cancer? Take a deep breath and be prepared to work for it by changing your lifestyle.

A landmark report from the World Cancer Research Fund says about a third of cancers can be prevented by choosing a healthy diet, being physically active and maintaining a healthy weight. As many again could be prevented by abolishing smoking.

"If all factors are taken into account, cancer is mostly a preventable disease," says the 537-page report, based on thousands of studies and written over the past five years by a panel of experts, including Otago University's Professor Jim Mann.

"The most important thing is the astronomically important role of obesity," said Professor Mann.

"This applies to a whole range of cancers, including two of the most common cancers, post-menopausal breast cancer and cancer of the colon.

"The other thing is the potentially important role of physical activity in cancer prevention, particularly cancer of the colon - not just with regard to obesity prevention. It seems also to be independently related."

More than 8000 people died from cancer in 2003, making it New Zealand's leading cause of death.

The report recommends maintaining a healthy weight and waist circumference (under 80cm for women and 94cm for men), eating plenty of fruit and non-starchy vegetables, and taking at least 30 minutes' of moderate physical activity a day - whether formal exercise or just vigorous housework - and preferably much more.

These suggestions go further than current official advice, which Professor Mann expected would now have to be revised - but the report's most controversial aspects are its challenge to meat lovers and heavier drinkers.

It urges limiting red meat (beef, lamb, pork and goat) and avoiding processed meats like ham, salami and bacon which have been smoked, cured or salted or which contain chemical preservatives. "People who eat flesh foods are advised to prefer poultry, and all types of fish, to red meat."

The report recommends restricting red meat intake to less than 500g a week cooked weight (700-750g raw), which equates to 71.4g a day. A typical steak can weigh 150-250g raw.

The Beef and Lamb Marketing Bureau says the recommendation is higher than the amount New Zealanders eat now. Bureau nutrition manager Fiona Carruthers says women eat 39g of beef and lamb a day and men 74g.

But other data she supplied suggest that if pork is included, the figures rise to 57g a day of cooked red meat for women and 110g for men, putting men well over the new recommendation.