And the move has even led to one mum taking her child out of school so she could eat a sandwich.
The scheme was introduced by St John the Baptist Church of England Primary School in Colwick as part of a healthy eating campaign for Key Stage One pupils.
The school provides a range of free dinners for the pupils, who no longer have the choice of taking in sandwiches. However, older children still have the choice.
One mum even took her four-year-old daughter out of school to Colwick Park on Friday so she could have a packed lunch of a cheese sandwich, cucumber slices, Mini Cheddars and a yoghurt and a chocolate mini-roll.
The parent, who doesn't want to be named, said her daughter often leaves the main courses and eats the desserts, and that it would be healthier for her to eat a 'balanced' packed lunch.
But the school said parents have been supportive of the move, as they want their children to "eat a wider selection of healthy foods."
The mum concerned said: "She nibbles at bit and bobs. I have tried to do anything I can, and I had to take her out of school on Friday to Colwick Park and she ate every single bit.
"I just want her to have a packed lunch, even if she has to sit away from everyone else."
She added: "I do not think it is healthier that my daughter can go without dinner and then have pudding. I can provide her with a full, balanced lunch box. There should be the option for children that do not eat it."
Chris Belton,headteacher at the school, said: “To promote healthy eating, we introduced a policy of mandatory school meals for those children starting reception year in September 2016 - and this applies as the pupils move up through the years in Key Stage One, where all pupils are entitled to enjoy a free school meal anyway.
"Apart from this case, we have received overwhelming support from parents who repeatedly tell us that it has encouraged their children to eat a wider selection of healthy foods.
“If children have any medical needs which mean they cannot eat certain foods, we will of course accommodate this and we already work with several parents and pupils across the school.
"At no point has the mum provided the school with any evidence that there are medical reasons which would affect which foods her daughter can eat.
"And when we have sat with her daughter at lunch times, she has eaten well, so we have no reasons for concern. In fact, only today she ate everything on her plate without the need for any encouragement.
“St John the Baptist is a church school and doesn’t have a catchment area, so parents make an active decision to apply for a place at our school. We make our policy on school meals very clear before parents apply.
“We have offered to work with the mum and her daughter and our cook to explore how we can encourage the daughter to eat lunches, but to date the mum hasn’t taken us up on the offer."
He added: "I would invite her to get in touch so the school chef and school team can support the daughter in enjoying a school lunch.
"For the first time this September, we have been able to choose own bespoke menu and this decision was made with the catering team, school managers and the school pupil council.
“As a governing body it is our long-term aspiration to be able to provide paid-for school meals across all of our year groups right up to Year Six.”
Key Stage One covers Years 1 and 2.
Another parent, who has one child in Key Stage One and one in Key Stage Two, at the school said she thinks the campaign is a "good decision".
She said: "I have seen some of the kids' lunch boxes that some parents send in thinking they are good lunches. Some are not good lunches at all.
"At least with school dinners they are going to be full, healthy meals.
"The school is providing free, healthy meals to all [the Key Stage One pupils]. I can't see why anyone would complain about it.
"If you go in and see them eat it it's not the case that kids do not eat it. Some of them wolf it down."
Councillor Meredith Lawrence, who represents Colwick at Gedling Borough Council, said: "Anything that gets children eating healthier is welcome.
"It's always difficult because children have fast food fads, with things that they will not touch.
"I would say the school has looked into this thoroughly. Anything to get children eating more healthily must be a good idea. You can see how children are targeted if you have watched children's television and seen the fast food [adverts].
"Parents and children need to be assisted into understanding what is good and what is not."
* A version of this story first appeared in the Nottingham Post.