Imagine a universe where plants were responsible for modern climate change, Earth Day celebrated deforestation, and Impossible Foods was developing this monster fiber-chicken.
Part of what’s made it difficult for me to turn vegetarian is I never feel full after a well-made salad. Even things like grain bowls feel a bit lacking sometimes.
High fiber salads should decrease gastric emptying speed. Grain doesn't have a lot of fiber or protein to break down so it shouldn't spend much time in your stomach in the first place. Amylases are generally doing their work in your saliva and small intestine.
You’re misreading the diagram. It’s showing the volume taken by the food. So assuming a similar density, owls being lower caloric value per gram means the owls would take a greater volume, which the diagram shows.