A friend of mine was heavy all his life. He had gastric bypass, which leaves room enough for your tummy to hold about 2-6 oz of food at one serving. He eats 5-6 oz of food 6 times a day.
He went from 410 to 180 (5'10") in 16 months.
IF IN FACT YOU ARE PREGNANT, dont get discouraged with weight gain, its normal , and most of all healthy for your unborn baby. I was 96 lbs all my life (5'2) and gained 60 lbs!!!!166! Thats alot on my petite frame, i literally looked as if i would explode. When my child was born, i was told by my hubby id NEVER be the same,, boy did i prove him wrong, in 4 months i was back down to 94, of course a severe colicky baby helped me lol. We are now divorced for 12 yrs lol.
Off topic, and rambling, but if your pregnant, your body will lose alot at birth, and the remaining water will not deplete itself from your body, until about 6 months post partum, then you can work with getting the extra fat off. Breastfeeding helps a great deal in weight loss after birth.