Let me tell you a story of when my wife was pregnant. Background:  WIfe was in the process of loosing weight, diet and exercise, when we unexpectedly got pregnant.  She was thrilled to be loosing the weight and determined to stay healthy through the pregnancy, so trying to eat right and still exercise.  There was a free consult with a dietician as part of our maternity care.   She goes to see the dietician (D) who gives her a quiz on what she's been eating and looks at her weight gain for the pregnancy so far (weight loss) and compares it to 'the chart'. D: You haven't gained any weight for the pregnancy, that's a concern. W: I've been eating lots of salads and doing some exercise as a continuation of the program I was already on. D:  You need to eat more and put weight on over the pregnancy. W:  My BMI is already too high, I need to keep control of my weight. D:  You should follow these eating guidelines, (shows portions and portion sizes). W:  I can't eat that much bread and other carbs, that's too much. D:  You need to eat like this to have a healthy baby. W:  Looks at young dietician girl who has a BMI that is too high, just a little look up and down. (She was a tall fatty).  Says nothing.  Dietician girl looks slightly embarrassed.  Wife does what she thinks is right. Result:  We had a perfectly formed, exactly average weight healthy baby and she weighed less fully pregnant than she had before she got pregnant.