This may not be especially germane, but here seems a fine spot to recount my tale of fat-replacement: Years ago, I worked a summer job in a factory that produced the powder that would be incorporated into foods from which fat had been removed, in order to keep them approximately food-like. The main ingredient was wood pulp. We’d get huge rolls of what looked like thick blotter paper. The rolls would be diced into ~1cm squares, and then the squares would be dissolved in hydrochloric acid. That slurry would be neutralized, by mixing ammonia into it, and then much of the moisture would be spun out. The pulp, at this point, had a consistency of dense fudge, and would tumble down a chute, at the bottom of which we’d collect barrels full, load the barrels onto pallets, and forklift them over to another part of the plant, where the fudge would be mixed in with a binder of some sort. It might be xanthan gum, or guar gum, or, most commonly, carboxymethycellulose, a/k/a CMC gum. That, to my knowledge, was the only ingredient that would show up on the package in the grocery aisles: whatever gum was used to stick the wood pulp to the rest of the food. This blend would be further dried and sifted into a fine powder, and shipped off to wherever people have had the fat sucked out of their food.
I remember this stuff went into Miracle Whip, and some kind of Sealtest fat-free ice cream-ish substance. Not sure who else our clients were/are, but I gather it’s a pretty common method for replacing fat in fat-free foodstuffs: acid- and ammonia-soaked wood pulp, blended with gum. (I know that the acid and ammonia neutralize one another, into something perfectly safely edible, but that doesn’t make it sound any less gross).