Caloric density is also pretty high in traditional diets like those of the Hadza, the Inuit, the French, the Argentines, and the Italians, but those produce low levels of obesity. So that can't be it. Those diets also don't include semaglutide.
Large portion sizes are real, but they are downstream of whatever is unnaturally increasing US appetites. Restaurants, housewives, and househusbands in the US don't serve 1500-kcal meals because they're in some kind of conspiracy to fatten your kids up for slaughter. They serve them because people complain if they don't.
The "ultra-processed" meme is clearly pointing at something critical, but it can't itself be the answer, because it's ontologically incoherent. As the post I linked above says:
> I’ve previously found [this meme] frustrating – it reeks of a sort of unreflective technophobia. What part of processing makes food bad? How does mere contact with a machine turn food from healthy to unhealthy? What food counts as “processed” or “not processed”? Is ground beef processed, since you grind it? Are scrambled eggs processed, since you scramble them? Is bread processed, since wheat doesn’t grow in loaves? Is water processed, since it goes through water processing facilities? Is the Eucharist processed, even though the processing only changes its metaphysical essence and not its physical properties? Everybody I ask acts like the answers to these questions are obvious, but everyone has different answers, and nobody can tell me their decision procedure.
So, is it corn? Missing micronutrients? Industrial polysaccharide thickeners? Fungicides like propionate? Nanoparticles of titanium dioxide? Antinutrients like phytate and citrate reducing bioavailability of polyvalent-cation micronutrients? Some combination? Lots of people have promising hypotheses but nobody knows. Anybody who claims to know is either lying or insane, often both.