Beth - If you are active 1200-1500 calories a day may not be enough. What I did was use fitday.com (free web-based program) to record what I ate on induction for 2 weeks. I stayed under 20 grams of carbs and didn't obsess over anything else. Then at the end of 2 weeks I decided wether or not this way of eating would work for me. I was the world's biggest skeptic, and now I'm a convert. I suggest you do induction for the 2 weeks recommended, without counting calories and see how you feel. I lost 9 lbs in that time.
To answer your question, Yes, if you totally disregard the calories forever, and say eat 3 lbs of bacon a day (4500 calories est.), you probably will gain some of the weight lost back. However, I doubt there are few people who can actually eat that much in calories.
Check out the daily thread, we've had conversations like this before, and there's better explainations out there.
SW 176.5/ CW 173.5/ GW 145