The ketogenic diet originated from the centuries-old observation that fasting has powerful neurological effects, including stopping seizures. A physician designed the diet to replicate this metabolic state, allowing patients to gain the brain benefits long-term without the danger of starvation.

Ferriss points to the emerging field of metabolic psychiatry, where dietary intervention is used for severe mental illness. He cites cases where schizophrenia patients, after years of failed medications, get off all prescriptions by adopting a ketogenic diet. This approach stabilizes the brain by providing ketones as a clean energy source.

The anxiolytic effect of ketosis has a clear neurochemical basis. Elevated ketones increase the levels of the enzyme GAD (glutamic acid decarboxylase), which converts the brain's primary excitatory neurotransmitter, glutamate, into its primary inhibitory (calming) neurotransmitter, GABA, creating a more stable neurological state.

The GSK3 inhibitor was developed for CNS diseases, requiring high specificity and the ability to cross the blood-brain barrier. These same pharmaceutical characteristics—potency and lipophilicity—proved highly advantageous for treating cancer, demonstrating an unexpected but effective therapeutic pivot from neuroscience to oncology.

The ketogenic diet has a profound neuropharmacological effect, acting as a brain stabilizer. It reduces levels of the excitatory neurotransmitter glutamate while increasing the main inhibitory neurotransmitter, GABA. This quieting effect explains its efficacy in treating epilepsy and anxiety.

In epilepsy treatment, patients often use the ketogenic diet for only 2-5 years. The fact that seizures frequently do not return after stopping the diet suggests it can induce lasting metabolic repairs and heal brain dysfunction, rather than just managing symptoms temporarily.

The ketogenic diet was developed over a century ago by a physician specifically to stop seizures. This medical origin, focused on brain function, explains its potential psychiatric benefits, reframing it from a modern weight-loss fad to a powerful therapeutic tool for neurological conditions.

A key benefit of ketosis is its mood-enhancing effect. It doesn't suppress positive feelings but significantly reduces negative mood swings, making it a powerful tool for mental well-being and a primary reason for its adoption beyond weight loss.

The common thread in mental disorders is metabolic dysfunction at the cellular level, specifically within mitochondria. This reframes mental illness not as a purely psychological issue or simple chemical imbalance, but as a physical, metabolic problem in the brain that diet can influence.