I think most Americans do not understand what is a healthy food and would think of a "balanced" meal of carbs, protein and fat, with fat being bad circa the 1960s line of thinking.
"I think most people know what’s considered healthy food. They maybe wouldn’t be able to perfectly break down ideal ratios of macronutrients, but they have a rough idea. The average person whose bad diet is making them unhealthy would probably be able to point to the bad diet as part of the problem. If I walked up to the average person and asked them to make an ideal meal plan for themselves to be maximally healthy, I think most people would do a decent job."
This is why most of america is stuck in diabetes land. I bet you most americans couldn't tell you the difference between if something is high in carbohydrates or fat.
A small detail you're missing is that in the US, sugar (usually in the form of corn syrup) is added to everything.
Example: I'd bet many people who are at least gen X grew up with PBJs as a staple food. It seems healthy enough: bread, peanut-butter, and a little jelly. However, today there's sugar added to the bread, sugar added to the peanut butter, and most certainly sugar added to the jelly, far beyond what it was when growing up.
If you aren't really careful when at the grocery store or making food from scratch, you can easily end up consuming a lot more sugar than you realize.
And just to add to your point: an European with the same level of knowledge and curiosity (me, an overweight unhealthy European) would not think a PBJ is healthy at all. For me, at least the PB and the J sound like „basically pure sugar“. We make the same misjudgments about other foods, but it’s entirely learned behavior. What I mean is: these judgments are rarely objective, but always subjectively derived from learned behavior.
> For me, at least the PB and the J sound like „basically pure sugar“.
As a side note, there is good peanut butter that is just roasted peanuts and salt. It’s pretty damn healthy — much more balanced and healthier than most breads or jellies.
It also tastes really good. If anyone reading this hasn't had peanut better which is just peanuts and salt, go buy some. Regular peanut butter doesn't taste good afterwards.
"I think most people know what’s considered healthy food. They maybe wouldn’t be able to perfectly break down ideal ratios of macronutrients, but they have a rough idea. The average person whose bad diet is making them unhealthy would probably be able to point to the bad diet as part of the problem. If I walked up to the average person and asked them to make an ideal meal plan for themselves to be maximally healthy, I think most people would do a decent job."
This is why most of america is stuck in diabetes land. I bet you most americans couldn't tell you the difference between if something is high in carbohydrates or fat.