Gave up pork for 3 years to prove I could. Am not and was not Muslim but knew a few in college and agreed with their opinion of pig meat. But so many Italian and other common (to me) dishes are pork based, so once the three years were over, I went back.

Also gave up alcohol for three years. That was much easier than giving up pork.

And intended to give up soft drinks for three years, but had no desire to go back after. Will be off them 9 years October.