Atkins to Italy

I have had great success on an Atkins lifestyle of eating and felt great for 7 years. I stayed the same weight for over five years. I ate lean, organic meat and lots of vegetables. However, I am heading to Italy, so I tried to transition to carbohydrates and gained 15 pounds! I am not used to counting calories or fats or even thinking about what I can or can't eat, but now I have to! I don't want to go or return from vacation even heavier than I am now. Hopefully, tracking my eating will give me information and feedback.