That means the only options left are micronutrients, specific additives or psychology.

I bet a lot of this is psychosomatic, you expect some food will give you fast energy so your body thinks that means you need it and releases insulin.

I was about to comment that the physical structure of the food and the fiber content also make a difference. For instance, rolled oats are available in different thicknesses, and the thicker ones don’t digest as easily. Brown vs white rice is another example.

But these examples have different glycemic indexes, which the study matched for.

And chewing. How fast it is eaten is likely affected.

Not only psychology, but training. If your body gets a load of sugar every time it tastes UPF additives, it learns to release insulin on taste to protect itself.

> That means the only options left are

plus all of the options that are complete unknowns which, in biology, is probably close to 99.999%

Another option is that it's affected by the order of consumption.

I know somebody who got really into blood glucose monitoring, and she tells me that the order in which she eats a meal affects how much it spikes her glucose. So if she eats a piece of toast followed by a piece of cheese, it causes her a bigger glucose spike than she'd get if she eats the cheese first and then the toast.

Looking at the two meals in the study: if I sat down to eat the processed one, I'd probably start with the veggie straws. If I saw down to eat the unprocessed one, I'd almost certainly start with the egg or the cheese.

edit: and here are some other options: I notice that the unprocessed one is grain-free, vegetarian and has significantly less sucrose. I don't know if any of that makes it more or less healthy, but they're significant differences nutritionally.