my DS nearly 7 is sooo thin, he eats like a horse, actually almost all the time, loves food and eats everything I give him. But he is so thin, I have never seen a child with so little body fat. I have checked his weight 3st 2lb and height 126cm and this gives him a BMI of 12.9 and under the 1st percentile. Would this warrant a GP trip anyone else with very thin kids?