They literally only eat for the camera, they probably just came off a 24 hour fast.
You can't just keep using the fast metabolism excuse when 90% of idols are thin and 90% of people aren't.
They only 'eat well' for the cameras because the fans comment. Please don't be naive.
There's been plenty of times idols revealed Vigorous diets that aren't healthy. And chances are all your faves are on them.