The last thing you should do is punish your grand daughter for not eating at school. She is only 5 years old and it could be that the noise in the school dinner hall is upsetting her and putting her off eating. I she is eating well at home then is there no way she could come home at lunchtime for her meals?

Go to the school and ask them for their advice, but please support your grand daughter in a positive way and try not to get upset with her, this is all very new for her and the change in her routine is obviously upsetting her. Be patient and good luck.