A comprehensive report by the American Institute for Cancer Research and the World Cancer Research Fund warns that medical evidence is stronger than ever that excess body fat increases a person's risk for numerous cancers.

The report, released today in Washington, says that carrying excess body fat boosts the risk for cancer of the esophagus, pancreas, colon, kidney and endometrium, as well as breast cancer in post-menopausal women.

Consumers are advised to avoid excess weight gain by limiting intake of high-fat and sugar-rich foods that are low in fibre, including hamburgers, french fries, pastries and sugary drinks.

The report by an expert panel also says there is more convincing evidence than a decade ago linking consumption of red meats like beef, pork and lamb to colorectal cancer. The panel says consumers should limit intake of cooked red meat to about 500 grams per week.

The experts say bacon, ham, sausage and luncheon meats should be avoided completely, and that every 48 grams of these processed products consumed per day bumps up the risk of colorectal cancer by 21 per cent.

In a separate recommendation, the panel says meals should be planned around non-starchy vegetables and fruits, served with such protein sources as poultry, fish or eggs. Probable evidence indicates they help reduce cancer risk on their own, and as low energy-dense foods, they help maintain a healthy weight, which the evidence shows has a big influence on cancer risk.