SUDDEN CHANGE IN HER EATING !!

[MollyMooMin]

My DD is 16 months and has ALWAYS been a brilliant eater! She's always eaten a very healthy diet and eats anything put in front of her..regular meal times, etc.
But, over the last week or so, she's pushed most of her food away, it's almost as if she's too busy to eat. Yet when we go to anyones house and they get the biscuits out, she's there like a starving dog! I don't mind her having the odd biscuit, but it seems that's all she enjoys eating at the moment. I s this normal for her age?