Not sure if this counts, but while I was living in France, for the last month I basically lived on eggs and merguez, with the occasional tomato and baguette. Now, Paris is filled with delicious food that I love, but I was so worried about how heavy I was getting that I decided in that one month (in which I was living entirely on my own with no social group to take me out to eat), I would go extremely low carb and low calorie. Well, it worked. My husband was stunned when I got back -- but moreso that I'd been living in Paris without indulging in all the great food that was around me.
Of course, I gained it all back...