Americans eat so much processed food simply because it is much cheaper than fresh food. Processed food is made to get consumers addicted (through convenience, taste, etc.) and encourage them to consume much more. Fresh food is almost the opposite.
I grew up in a country where freshly made food is actually cheaper than processed food, even to this day. People who stick to a traditional diet are mostly thin, while those who stick to a processed food diet gain a lot of weight.
When I was visiting the US I was shocked how much more expensive “real” food is. Here I am spending more if I eat out or processed food versus cooking my own food at home. In the US it was basically the inverse, didn’t make any sense to me. (N=1 and 10 year old experience, but it seems to have only gotten more extreme since)
I love my meat but if I switched to a vegetarian diet it would be trivial to make varied, delicious meals at $1.50-$2 a portion.
I guess we could have beans and rice every day, but I don't think it's a lot to give my kid a varied diet based on what's in season. Out of season is awful and that's how I ended up spending $15 on berries my kid wanted.
When people talk about these cheap meals, I wonder if they just expect everyone to eat the same thing every day at the lowest quality. I can go to a budget grocery store and get $3 eggs. That's true, but I feel like the local national chain should ve a good enough yard stick.