The Royal Society for Public Health says mums and dads need support rather than a letter.
Steve Bownds, Development Manager at Youth for Christ (YFC) thinks this has the potential to be a positive idea.
He told Premier's News Hour that receiving a letter can be upsetting for some families: "I think potentially a kindly worded letter that's part of an on-going dialogue could be a useful thing, but getting a letter out of the blue - I can see why people might find this difficult and frustrating to handle."
In England pupils are weighed in their first and last year of primary school.
"I think it's something that the whole of society - from parents through to schools, through to church, and obviously government and the people who supply the food could be doing more to help - it's a massive issue," Steve Bownds told Premier.
He said that everyone has a role to play in telling children they are loved, but also ensuring they are healthy and safe.
Listen to Premier's Marcus Jones speak to Steve Bownds here:
