Should unhealthy fast food products be sold with a warning label?

For some reason I feel like this prompt is directed towards 10 year olds.  Fast food doesn’t need another “warning” label, seeing that nutrition facts can be found.  If any food is unhealthy people will find out about it someway or other.  Besides, how would one classify “unhealthy”?  You can’t make some arbitrary line where everything on one side is healthy and everything on the other is unhealthy.