"as a slight aside, if a child shows up as large all round, stomach, legs, head, the works on their 20 week scan, is 91st centile at birth for weight and height and continues to grow along the same centile lines, are you saying they're really obese and the parents are deluded? Are they supposed to be put on a diet?"
Twoistwice - yes and no.
A baby who is 91st centile is not considered overweight. A 2 year old who is 91st centile is not considered overweight. But if you go above the 91st centile at school age (5 years old) then you are just on the edge of overweight - in that if you are 98th centile, you are now overweight, whereas a 98th centile toddler is not.
This is information I found out in relation to my son, who was born at 98th centile and followed the 98th centile to his 2nd year. He seemed to be following his centile and I wanted to know if that was actually going to become a problem at some point.
Thing I found, however, is they turn 2 and its like flicking a switch, suddenly they are picky and dont necessarily eat what they used to. I moved him onto semi-skimmed milk at 2, and apart from not having many sugary snacks (he has some, just a few times a week instead of a few times a day) he is now on the 75th centile. Also, I didn't let him down loads of apple juice etc as drinks as this was calories I felt he simply didn't need. Not dieting him, as such, just exercising caution.
My daughter weighed 12 kilos at 6 months old. I dont know what she weighs now at 9 months old, I weighed her at 6 months to see whether the car seat was still safe. As far as I am aware, for a girl, that is off the centile charts. She is also off the centile charts for height - as was my son at that age - he was always in proprtion, she is slightly fatter than she is tall but not by much.
But I'm not worried about it - I'll do the same with her. Semi skimmed when I move her to cows milk, no drinks with calories apart from 2 milks a day, very few sugary snacks, and hopefully the toddler pickies will kick in and help her level out too.
Also, I let them charge around as much as they like, even if its giving me a headache.
If I had a child who had a genuinely insatiable appetite though, that would concern me more. But she eats less than her brother did at that age - so I suspect she will level off even quicker than he did. I hope so anyway - she has sumo wrestler legs, she's not going to make a very dainty ballerina at this rate...