Colon cancer.
http://www.bbc.co.uk/news/health-11264372
"If UK trends in obesity and activity stayed as they are now, the predicted figure of approximately 35,000 cases a year is reached by 2040."
"And if the UK managed to match levels of physical exercise in The Netherlands - the best among the countries studied, that would prevent approximately 2,000 cases."
Cycling isn't actually mentioned, but... earlier this morning the story was illustrated with a picture of a large bike park somewhere in the Netherlands.
Wonder why they changed it?