Brain cannot utilize -

Alts, is 'b' i.e., Fatty acids There is no stored fuel in brain2, but it utilized 60% of total energy under resting conditionsQ.Glucose is virtually the sole fuel for the brain2, except in prolonged starving when ketone bodies are the majorsourceQ.Fatty acids do not serve as fuel for the brain, because they are bound to albumin in plasma; hence cannot cross blood-brain barrier.