You simply CANNOT gain 1lb of fat on 1200 calories. It's a physical impossibility. It's far more likely that you ate some salty foods and retained about 1 lb of water. I'm not saying that the scale didn't go up. I am saying that it CANNOT be fat.
So a few thoughts for you.
1 - at 5'8" and 255 lbs, 1200 calories is too low. If you went UP to 1200 calories, it's no wonder your weight loss stalled. I'm 5'4" and 165 and am losing quite well on 1500 calories. If you use this calorie calculator (
http://www.freedieting.com/tools/calorie_calculator.htm) and put in your stats (I guessed your age at 30), then your maintenance calories are around 2600 a day and your fat loss calories are 2100. You could probably even take that down as low as 1800 if you wanted and still lose quite well.
2 - Many people lose a lot of weight at first - most of it is water weight - and then when they slow down to a normal and healthy rate of loss, they get all discouraged and freaked out because they're not still losing 5lbs a week and they quit. That's the wrong thing to do. THIS ... this slower, healthier weight loss is the real loss. This is when the actual FAT is coming off, not the water weight and the retained fluids.
3 - It is perfectly normal for our body weights to fluctuate from day to day and even from hour to hour. There are many, many things that will affect your weight: the amount of sodium you've consumed, the types of foods you eat, the amount of water you drink, the amount of exercise you do, the clothes you are wearing, the time of day you weigh, the temperature and humidity when you weigh, whether it's your TOM or not, whether you're ovulating or not, whether you have allergies or not, whether you've just drunk a glass of water or not ... see? So many things can affect your weight loss. The most accurate way to weigh yourself is to pick the same time, location, and clothing and keep it all the same every single time you weigh. I do my daily weigh, in the morning, right out of the shower, wearing nothing but panties.
4 - If you're eating things like Lean Cuisines, then I will almost guarantee that your increase in weight is sodium. Processed foods are VERY high in sodium and will often cause you to retain water.
5 - You don't say if you're doing any exercise, but combining a reasonable diet (i.e. not rock bottom calories) with some exercise will help with the weight loss.
6 - Our bodies aren't machines. You simply cannot calculate calories in and calories out and have it work to a mathematical formula (unfortunately!

). We are all different and sometimes you have to tweak as you go along to see what works best for you.
I would take some time to read through a lot of the stickies posted at the tops of the forums. There's a TON of good information there about how weight loss happens, what can make your weight fluctuate, and some pointers on how to get started and keep on plan!
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