Junk food is one of those "I know it when I see it" type of things for Public Health. It (currently) has no formal definition, yet lots of organisations want something to be 'done' about it.
However when someone comes up with a 'definition' of what junk food it, it inevitably encompasses things that any normal person wouldn't consider junk food.
Transport For London/London Mayor Sadiq Khan, FarmDrop
But of course it won't. Because there isn't a childhood obesity epidemic, and because kids don't go doing the weekly shop. Regardless, there has been some... disagreement about what 'junk food' actually is. One 'purveyor of food' disagreed with TFL's opinion..
Naturally FarmDrop deny that they sell junk food. Exactly what an organisation that sells junk food would say...
- https://health.spectator.co.uk/the-proposed-junk-food-ban-is-aimed-at-you-not-your-children/ The proposed ‘junk food’ advertising ban is aimed at you, not your children] - Christopher Snowdon, Spectator Health
- TfL junk food ads ban will tackle child obesity - London Assembly(archive)
- Can You Spot The Junk Food In This Ad? TfL Could - FarmDrop (archive)