A full stomach doesn't like studying
The 1. and 2. Breakfast is easy to digest and not a burden. Lunch is different: If there is fried or boiled meat, then it makes you pretty tired.
In addition, this time usually falls into midday. And then do schoolwork? This can not go well. Give your child a break after school and lunch, but make an exact appointment, when which tasks are done. In the first years of school, some children want to do the tasks before they even eat. If that works – all the better, because now the biological performance is still relatively high. From 16.00 Clock it looks good again. But don't let your child push the chores into the evening - it just spoils the day.