It was definitely not enough time for them to finish a normal lunch between the short time gap from 1:05 to 1:15.
In my case, I swap the lunch with the breakfast for my daughter. In other words, I give her a big meal from 10:00 to 10:30 and prepare some snack for her to eat after the interest class.
In case she cannot finish the snack, class teacher will let her finish them during the normal snack time.
I am just thinking, perhaps I can feed my kid some rice before he goes to school, and let him eat some bread or biscuits before the lesson starts. I think this may help a bit.