This is interesting and clashes with my personal experience. I eat two vegetarian meals a day which usually include beans, eggs, or oats. In my experience meat is considerably more satiating than meals with beans or eggs but less satiating than the meals with oats.
I experimented with vegetarian meals a few months back and found I could eat literally 1kg+ of cooked lentils/beans/etc and still feel hungry. <500g of chicken breast (plus vegetables), on the other hand, would see me through.