To answer you original question Hinata I'll repost what I said in another forum to someone with the roughly the same question. Oh, and by the way, 1,000 calories is WAY to little. Your body is storing every thing you eat as fat, because it thinks it is starving:
Well, I'll relate a little experience I had with extremely low cal. diets. It is widely known that you need to cut calories in order to lose weight but BE CAREFUL in your cutting.
When I first began losing the vile cancer-weight, I cut my calories from a normal 2600 or so, to 1300, and a few weeks later I was up 10 lbs but excersizing like a mad man. I felt sick, weak, and terrible all around. I couldn't figure it out. So I went to the doctor (who was also a nutritionist) and she shouted saying, "Whoa! You can't dramatically cut calories like that! Not to mention males should not dip under 1800, especially if they are active. Females not below 2000 to 2100 if they are active."
When the body is all of the sudden depraved of calories it "prepares for the winter" as it were, and stores damn near all you eat as fat. Which is why the constant hunger and lack of energy never seems to subside. See what people don't realize is that thier "normal diet" -or what they think is normal to all people- is probably 3,000+ calories. Then when they start counting they drop it radically not realizing what they were eating before. Not to mention the "crash diets" where you shatter your intake completely rather than stepping down, or just going to the normal 2,000 or so level with excersize, has a VERY high percentage rate of falling off the wagon.
Also take into account WHAT you eat. Eating a big salad with strips of grilled chicken, will REALLY fill you up, but be next to nothing on calories, meaning you can eat more through out the day.
Long story short: When I watched better WHAT I ate, and ate more calories, the weight melted off. Now if only I could brake that damn plateau I am at now.