Apparently though meat (and eggs, etc) are a relatively minor part of their diet, composing something very low like 5%. Again though, they're not really referred to as herbivores they're usually referred to as frugivores, to distinguish their eating habits from that of say a cow or a horse.
I do sometimes wonder if we are simply frugivores evolving to be more carnivorous (as I may have said), but I am unclear on what stage of his evolutionary process we are at (whether it ever finished, or whether we are in a limbo state. And if the latter, are we closer to frugivores or carnivores, etc etc).
And yes it is true that our brains are very energy-hungry. I learned about this when studying anthropology. It's logical that meat aided in brain development due to it being energy-dense. As for the fat content I really don't know. Do our brains benefit from a high fat diet?