People under 50 are experiencing an alarming rise in bowel cancer, and a diet of too much meat and fast food may be to blame, cancer experts in the United States say.

Bowel cancer incidence rates have remained stable or decreased in older people for more than a decade in the US, largely due to screening tests such as colonoscopies, which are recommended for people over 50.

An increase in red meat consumption is contributing to the rise in bowel cancer in younger people, researchers say.

However the study, published by the American Cancer Society yesterday, found incidence rates of colorectal cancer in those aged 20 to 49 increased 1.5 per cent a year in men and 1.6 per cent a year in women between 1992 and 2005.

The biggest rise was seen in those under 30, where rates rose by 5.2 per cent a year in men and 5.6 per cent a year in women. In sharp contrast, rates for the over-50s are now dropping 2.8 per cent a year in men and 2.2 per cent a year in women.