In mid-2012 I decided to become a vegetarian, both for health and ethical reasons. Before then I had mostly been on autopilot when it came to food - I just ate what what was the norm in my family. My choice forced me to get out of my comfort zone, to try out new foods I had never considered before. For this reason, the change has been incredibly positive to me; I'm much more conscious of what I eat now. And by setting a precedent it later helped me make more changes, like cutting down sugar. I'm currently testing to see if the bloating and stomach aches I suffer daily are because I am lactose intolerant; if it is indeed the case, that will require another drastic change, although this particular one will be by necessity rather than choice.
What is the biggest change you've ever made to your diet? Was it by choice, or did you feel obligated to do so, for example because of health issues? What did you get out of it? How much thought do you put in your daily diet, in general?