TLDR: According to the article, people eat more calories when they eat ultra-processed foods. The reason is unknown, one possibility is more calories per bite as manufacturers remove water and some other ingredients during processing.
Overall, a pretty underwhelming article. Not surprising, unfortunately -- I have been subscribing to the Economist for over 15 years since late 1990s until the slow erosion of quality made me drop it.
Yes, I agree with you, the Economist from the 90s was a different animal. If you ask me the above article is just paid shilling for Ozempic et. al. Not directly obviously, but in the mindset and viewpoint it wants to develop in readers
ultra-processed people by chris van tulleken hypothesizes that it's because the food is less nutritionally dense through extraction and reconstitution to more palatable and economically expedient forms. additionally, these forms require less effort to process by chewing so we're able to ingest more calories more quickly before our biochemistry can catch up and signal that we've consumed what we need. finally, the processing of food breaks down the original nutrient "matrix" in the way that our metabolism evolved to process it. we evolved to metabolize an apple, i believe was his example, by eating it raw and in its original form, together with all that constitutes an "apple" and not simply the composite of nutrients that we can extract from an apple. the hypothesis is that the whole apple influences our biochemical response differently than the extracted nutrients that have been reconstituted in a different form.