For another anecdote, my wife's friend worked at Starbucks in Canada and in Japan. She said the Frappuccinos in Canada use around double the amount of syrup than those in Japan.
> how much of a punch in the face of sweetness/richness literally everything available in US restaurants is
Yeah, too much sugar/salt/syrup/condiments, too many artificial ingredients on things. Today I was talking to my wife how the Cheetos here is not so good, as it has a weird orange color and the taste is way too much superficial. The cheese too. too many cheddar varieties with colors that doesn't seem like something made out of milk.
The sweetness is another major put off. There's no concept of a savory snack here. There's also no culture of an afternoon or tea time snacking. In my personal opinion, having a small post-lunch snack helps me stay satiated for longer and have a much smaller supper instead of a large dinner.
Why is it so Easy to be Thin in Japan?
Spending has dropped because there are such large subsidies to cheap carbs, and that is the bulk of many people's diets. A steak and veggies is no cheaper than it was 40-50 years ago, but we're eating far more refined junk with additives because it is cheap and convenient.
I believe the leading hypothesis is that being rich absolves you of the stressors that make junk food attractive. Others are, as you mentioned, the ability to buy more expensive food with more nourishment/satiation per calorie ("protein leverage hypothesis"), or access to nature and refuge from pollution (it's certainly the rich people where I live who ride bicycles.).
Regardless, a poor person from 50 years ago couldn't buy the cheap sugary crap even if they wanted to.
That is, the point of the parent's post was not obviously "crap food is so much cheaper than high quality food", but as most naturally read as "because we can afford more food, we're buying and eating more"
My point was "if that logic holds, I would expect the rich to be significantly fatter than the poor". Which, as you note, is not the case. Nothing more.
Other restaurants have retired round plates and serve meals on platters.
[1]https://www.youtube.com/watch?v=Q2UnOryQiIY
[2]https://www.amazon.com/Big-Fat-Surprise-Butter-Healthy/dp/14...
If you dig more into it, you'll find the obesity crisis started around the late 70s with a change in dietary guidelines and medical guidelines saying basically 'fat & meat bad' and 'carbs good' along with the widespread introduction of vegetable oils, leading to too much insulin and other hormonal effects slowly increasing diabetes & obesity in our population. Also food companies honing on what obesogenic combos of food lead to people to eat more, buy more and thus get better sales.
Read "The Obesity Code" if you want a more detailed description with a lot of links to papers and studies for more info. [0]
[0] I said this yesterday too in another article: https://news.ycombinator.com/item?id=25767604