I think that's right, reducing refined carbs and processed foods, etc. is a huge start, and bound to result in great improvement. So that's part of it. But animal sources of food have certain beneficial micronutrients that are lacking in plant food, and that's what would worry me most, aside from the fact that grains and legumes (and even seeds and nuts in high quantities) have high levels of antinutrients (e.g., phytic acid) and are not the best sources for the nutrients that they do offer (veggies being much better). But if people are seeing improvement and better health from such diets, then by all means. The human body and nutrition itself are quite complex, and there's much we don't know.

And thanks so much for sending the paper.