Caloric intake effects blood flow and the ability to sustain thought, but *intelligence* is a particular ordering of synapses with only ancillary correlation to brain size/bloodflow.
Yes, and my understanding has always been that the popular belief that intelligence directly correlates with brain size is, at best, unproven.
I've heard surface area (reticulation) is a bigger indicator than overall mass. But all are downstream of how it's been constructed, from the inside, over time.