In May 2019, the journal Cell Metabolism published the results of a small randomized, controlled study comparing two diets: minimally-processed foods vs. ultra-processed ones. According to the article, this N.I.H. study is the first to show causality between degree of food processing and human weight gain. When dinner is chicken tenders and french fries instead of home-cooked roast chicken and baked spuds, we pack in more calories--because we overeat.
Why are people eating more calories of ultra-processed food in each sitting than minimally-processed ones? Food Guys Jon and Greg speculate: fried coatings, salt and sugar enchant us, and a soft consistency sends it down the hatch before we can register, "Enough."
Lead author Kevin D. Hall says: “The next step is to design similar studies with a reformulated ultra-processed diet to see if the changes can make the diet's effect on calorie intake and body weight disappear.”