Earlier quoted context omitted.
The difference can be explained in large part by urban design: many US shoppers need a car to drive to the supermarket and only go there once a week or less. In Europe you live much closer to a supermarket, so you go more often and get more fresh food and less frozen or canned. Some Americans are surprised to learn that many supermarkets inside cities do not even provide parking, everyone walks or bikes there. People…
That makes no sense. If the average American can drive to the supermarket, they're even more likely to go more often than if they had to walk.
When I lived in Europe for a couple months, my first time there I grocery shopped like an American - filled up an entire cart with a week or two worth of groceries and then everyone stared at me when I checked out.
It's absolutely true that Europeans who live in walkable cities go to the market to pick up groceries a few times a week. Americans simply do not, with very few exceptions.
The grocery store density is much higher though. There were at least 2 grocery stores within a 5 minute walk from anywhere I've stayed in a city core in Europe. At least a dozen within 15 minutes.
It's simply a difference in culture. There are plenty of places in the US where you could drive to half a dozen grocery stores within 15 minutes but people simply don't do so. The store sizes reflect this cultural difference too. The average grocery store in the US seems to be 4-6x larger than those in Europe.