There's a PDF of the actual menu, although it's just as random. Apparently wheat flour pasta is unprocessed, but a wheat flour tortilla is ultra-processed, sure, okay.
Day 1 Dinner: Canned Corn (Giant brand) is considered "ultraprocessed".
Wow. I appreciate the link. Honestly, seeing the menu makes me think it is somewhat quackery. But it seems like Scientific American really did represent this study correctly.
The main thing I've noticed is that the "ultraprocessed" foods are low in fiber, and they try to make it up with large doses of "NutriSource Fiber" pretty much every day.
There are exceptions: Canned Corn (wtf?) makes it on the list of "ultraprocessed", and has decent fiber from my memory. A few days later they have beans + beef. But otherwise, the primary source of fiber in that diet is artificial Nutrisource Fiber.
Dietary Fiber is core towards feeling full. Its no secret to me (at least) that more fibrous foods (even when low in calories) fill me up quicker than fiber-free foods. I can eat 2 or 3 500+ calorie donuts for example, but trying to eat 800-calories worth of "ultraprocessed" canned corn (that's 1.5 kg / 3.3 pounds of corn) is simply infeasible in one sitting.
Or to put it another way: 800 calories in corn is roughly 3x 8.5 oz cans of corn. Still "ultraprocessed" (lol) according to this study, but its going to be way healthier than drinking diet lemonaid with Nutrisource Fiber.
There's a PDF of the actual menu, although it's just as random. Apparently wheat flour pasta is unprocessed, but a wheat flour tortilla is ultra-processed, sure, okay.