EXCESS weight caused almost 5,000 cases of bowel cancer over the past 10 years, according to Cancer Research UK.
In a BBC News report, the charity described the findings as a “huge worry” and called for more to be done to promote healthy living.
There are around 3,800 cases of bowel cancer diagnosed in Scotland every year, with 1,600 people dying from the disease annually.
Obesity is linked to 13 types of cancer with Cancer Research UK citing resistance to insulin, a hormone important in the breakdown of food, as one likely explanation. High levels of insulin in the body has been found to cause cells to divide more rapidly, raising the likelihood of the cells changing and leading to cancer.
The charity warned that the proportion of bowel cancer cases caused by obesity is on the increase as more of the population becomes overweight. It claimed shoppers were "bombarded" by offers encouraging them to stock up with food that leads to weight gain. It now wants a restriction on such multi-buy deals.
Professor Linda Bauld, Cancer Research UK's cancer prevention expert based at the University of Stirling told the BBC: “It is a huge worry to see so many bowel cancer cases being caused by excess weight, and to see that proportion rising as more of the population becomes overweight or obese.
"It is also now more common for adults in Scotland to be overweight or obese than a healthy weight.”
She said the Scottish Government’s planned new diet and obesity strategy was a “once-in-a-generation opportunity” to make a positive impact on people’s lives.
The strategy is expected to consider measures such as the use of multi-buy promotions as well as encouraging the food and drink industry to develop healthier choices and to reformulate products with less calories, salt, fats and sugar.