You are not going to be able to eat an extreme low calorie diet during your pregancy, such as Medifast, etc.
You can watch your calorie intake, but you need to be sure that you are eating enough to fuel your needs, as well as those of your developing baby. Medifast averages around 1,000 calories a day, and many plans such as calorie counting, Weight Watchers, and others average 1200-1800 per day. For an expecting mother, most references recommend eating 2000 calories per day on average, which is considered more of a "maintenance" level of calories, during your first trimester.
In the second and third trimesters, you would need to add 200-300 per day, because the last two trimesters is when the most size/weight development happens in the baby.
You cannot expect to start out at 197 pounds, and stay under 200 for a pregnancy. You simply can't, in most cases.
What needs to be understood, is that there are many changes that are going to happen weight-wise, that have nothing to do with fat. The baby will weigh 5-9 pounds on average. The placenta can weigh 1-2 pounds. The bag of amniotic fluid can add a pound or two by the end of the pregnancy. The uterus itself goes from the size of a lime, to large enough to house the baby, placenta, and the amniotic fluid. The uterus will weigh more than normal at the end of the pregnancy as well. Also, many women gain a full cup size or more in their breasts, and they get heavier, during pregnancy.
These reasons are why the recommended weight gain range (for women of average weight) are often in the 25-35 pound range, and 10-20 pounds (for women who are overweight). A lot of the weight gain has nothing to do with actual fat.
I recommend that you speak with your doctor, or a nutritionist, about your concerns. I recommend staying active-walking, prenatal workouts, etc. during your pregnancy. Have your doctor suggest a guide to eating that will help keep you more fit, but will be sure to keep you and the baby in optimum health during your pregnancy.
I understand your concerns, and I have been there myself. I have lost weight successfully, and have had to gain some back with each baby, and start over again. However, it is a temporary situation.
Please speak to your doctor, and see if he/she can recommend an eating regime for you to guide you through this. Some gain is normal and expected, but you might be able to stick with a guide, and with regular exercise, have a moderate weight gain for your pregnancy-rather climbing up 50 pounds. (A happy medium.
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