Food for intellect?

Thao in The Book mentioned that once on Earth there was a plant that could stimulate brain activity to activate the intellect but it was only used by the people in power. Do you know of any natural plants on Earth that could still do this Tom, and still be safe to consume?

K.K.

No. I use fasting (as described in my first book The Joy of Perfect Health to access extra resources of the mind. Apparently, metabolism engages considerable conscious resources. Do you feel like "thinking" or reading a book after a large meal? Don't you feel sleepy and tired after a large meal?

Tom