@sinnerman That article is much better, thanks for sharing it! I’d never thought of ultraprocessing as predigestion before.

For a time, Kevin Hall, a nutrition and metabolism scientist at the National Institutes of Health, was also skeptical that ultra-processed foods were harmful.

To test the idea, he designed a study that compared what happened when men and women were recruited to live in a lab and fed different diets. In one phase of the study, the participants ate mostly ultra-processed foods for two weeks. Their daily meals consisted of things like honey nut oat cereal, flavored yogurt, blueberry muffins, canned ravioli, steak strips, mashed potatoes from a packet, baked potato chips, goldfish crackers, diet lemonade and low-fat chocolate milk.

In a second phase of the study, the participants were fed a diet of mostly homemade, unprocessed foods for two weeks that was matched for nutrients like salt, sugar, fat, and fiber. Their meals consisted of foods such as Greek yogurt with walnuts and fruit, spinach salad with grilled chicken, apple slices, bulgur and fresh vinaigrette, and beef tender roast with rice pilaf, steamed vegetables, balsamic vinaigrette, pecans and orange slices.

In both cases, the participants were allowed to eat as much or as little of the foods and snacks as they wanted.

“If it was really about the nutrients — and not about the processing — then there shouldn’t be any major difference in calorie intake between these two diets,” said Hall. “I thought that was going to be the result of the study.”

But, he added, “I was hugely wrong.”

When people ate the ultra-processed diet, they consumed substantially more calories — about 500 more calories a day compared to when they ate the mostly unprocessed diet. The result: They gained weight and body fat.

The researchers also noticed a difference in how quickly the participants consumed their food. They ate the ultra-processed meals significantly faster, at a rate of about 50 calories per minute, compared to just 30 calories per minute on the unprocessed diet.

Fascinating.