The ones that are telling you that 1200 is waaay too low are right.

I've lost over a hundred pounds and I still don't eat that few calories - I'm sitting around 211 pounds at 5'9" and consume more like 1470/day. I'd lose my damn mind. It's slower, but it's what works for me. I learned that after years of doing the same thing and years of failing. This has to be a lifestyle change, so you must learn new and healthier habits.

If you know this is how you fail, then stop setting yourself up to do so! You know you can't maintain such a large deficit, so don't. Set your calorie goal at something more attainable, like 1600 or 1700. That's still 2 pounds a week! Get used to eating less and logging consistently. As you lose weight, you'll revise your goal downward.

Know your weaknesses. If you're a MUST HAVE CAKE kinda girl like myself, then plan for a maintenance day every other week or build an allowance into your day or week for the thing you just can't say no to. Don't let the craving build into a binge. You aren't swearing off anything for the rest of your life, right? Learn to substitute or how to fit it into your goals. You've got this!