[kritiko]

Are you familiar with Kevin D. Hall's Ultraprocessed food study?

https://www.cell.com/cell-metabolism/pdf/S1550-4131(19)30248...

They did it in a metabolic ward, so about as controlled as you can get in a diet study. Created 2 diets that were matched - so caloric density and macronutrients of the food were the same. Let people eat as much of the food as they wanted, and the ultraprocessed group consumed 500 calories per day more.

[crazygringo]

Thanks for linking that -- it's a rigorous study for what it attempts.

However, there are two fatal flaws. The first it that it neither controls for nor even measures the glycemic index of the two diets, and the second is that it neither controls for nor even measures the vitamins and minerals in either diet.

The major critique around dividing foods into "unprocessed" vs. "ultraprocessed" is that high-GI foods like rice and raisins are considered unprocessed, while lower-GI foods like pasta (and zero-GI foods like hamburger patties) are considered ultra-processed. And in this study, the authors could assemble whatever GI they wanted for each diet, and never revealed it.

But there's a clue -- in the study, the additional calorie intake and weight gain in the "ultraprocessed" diet is entirely consistent with a vastly higher GI of that diet, which is almost certainly indicated by the nearly doubled non-beverage energy density (2.147 vs 1.151, Table 1).

Which means the study is actually entirely consistent with the idea that higher-GI foods lead to weight gain, and that "ultraprocessing" itself is entirely irrelevant.

[kritiko]

The study’s author, KevinH_PhD is a good follow on Twitter and generally responsive to his critics there:

“Glycemic index was calculated to be ~52 for both diets with respect to oral glucose. There were no significant differences in CGM determined mean glucose or glycemic variability as assessed by glucose CV.”

From this thread - https://twitter.com/KevinH_PhD/status/1536782331628822528