Most of the measures you suggest seem to be centred around teaching children, conditioning children and banning things from children.
However, I think we need to think more about why people overeat, and then address that problem directly. It's closely related to why they smoke, why they gamble, why they take drugs, even why they swear. It's not just a health issue. Trying to coerce people into being 'virtuous' often has the opposite effect to that intended: one of the reasons why teens smoke and swear is seemingly because they know that authority figures don't like them to, for instance. Trying to live up to the expectations of other people is tiring and stressful; people look for ways to relieve that stress -- guess what they choose.
Imagine having your car drive off and park itself somewhere. You don't even need to know where.
And there are wider and more fundamental social benefits. City centres will become pleasant places to walk in. Cleaner air, less noise and less chance of being run over. Another example, children will play outside more, rather than being confined indoors as they increasingly have been.
Why park it. You'd surely want it to earn it's keep ferrying your "friends" to work [depending how restrictive laws are on temporary rental of autonomous vehicles], dropping-off the kids, popping to the drive-thru to get your lunch, picking up your washing, getting your supermarket shopping and such.
However, I think we need to think more about why people overeat, and then address that problem directly. It's closely related to why they smoke, why they gamble, why they take drugs, even why they swear. It's not just a health issue. Trying to coerce people into being 'virtuous' often has the opposite effect to that intended: one of the reasons why teens smoke and swear is seemingly because they know that authority figures don't like them to, for instance. Trying to live up to the expectations of other people is tiring and stressful; people look for ways to relieve that stress -- guess what they choose.