Fizzy drinks, cakes, biscuits, crisps and desserts have all been identified as risk factors for bowel cancer, according to new research.
The study is the first of its kind to find a positive link between the disease and a diet high in foods that contain a lot of sugar and fat.
Researchers looked at risk factors including diet, levels of physical activity and smoking in a large Scottish study.
A team from the University of Edinburgh examined more than 170 foods. These included fruit, vegetables, fish and meat, as well as high-energy snack foods like chocolates, nuts and crisps and fruit drinks including fruit squash.
Scientists reported links with some established risk factors of colorectal cancer – such as family history of cancer, physical activity and smoking. They also identified new factors including high intake of high energy snacks and sugar-sweetened drinks.
The study – which used data from the Scottish Colorectal Cancer Study – carried out in 2012, builds on previous research into the link between bowel cancer and diet. Those studies identified two distinct eating patterns – one, high in fruit, vegetables and other healthy foods and the other – known as the western pattern, which is high in meat, fat and sugar.
The healthy dietary pattern was found to be associated with a decreased colorectal cancer risk, while the western dietary pattern was found to be associated with an increased risk.
Dr Evropi Theodoratou, of the University of Edinburgh's School of Molecular, Genetic and Population Health Sciences, said: "What we have found is very interesting and it merits further investigation using large population studies. While the positive associations between a diet high in sugar and fat and colorectal cancer do not automatically imply 'cause and effect', it is important to take on board what we've found – especially as people in industrialised countries are consuming more of these foods."
The study is published in the European Journal of Cancer Prevention.