The government minister in charge of education says pupils should be banned from leaving school grounds at lunch time to stop them eating junk food.
Ed Balls wants more kids to eat school dinners to encourage them to eat healthily.
The Schools Secretary says while he won't force secondary school head teachers to bring in a ban, he will support those who do.
Mr Balls is also calling for councils to stop takeaways opening near schools.
He's expected to tell the Healthy Eating in Schools Conference in London that there's "no point" banning junk food in schools if kids can get it from nearby shops.