The diet of most people in the US is pretty horrific. Absurd amounts of sugar, little to no vegetables, little fiber, lots of heavily processed foods.

That certainly does not help the situation. Whether it's correlational or causal I'd leave up to people more knowledgeable in the subject.

Most people don't care. What you're talking about is way more work than 99% of people want to put in. They have a TV, it has a youtube button on it. They click, they watch. Anything else is irrelevant.

>0 is too much, in my view.

Ads are a toxic weight on everyone who views them.

I use ad-blocking as much as possible, along with things like SponsorBlock to skip such content within the video itself.

That is not even close to feasible with today's level of technology, and will not be for quite some time.

That site could use a little more. Maybe a count of how many in the current month and year, tallies for each year, maybe even trends. Could be nice. :)