As someone else said ... pfffft. DS2 turned 3 one month ago and is 17.8kg. However, he's tall and a solid build. He's a bigger boy all round compared to many others his age. No one has checked his BMI and no one is going to as he's not overweight. He's just a big, healthy boy whose diet is - mainly - very good. Do not listen to any talk about your child being overweight if you know she's not.