SSC Selection Post 2022 PYQ — Question 30

The correct answer is option 4 i.e. Only glucose.

During periods of fasting, starvation, or when glucose is scarce (like on a ketogenic diet), the brain can switch to utilizing ketone bodies for energy. These are produced by the liver from fatty acids and can effectively cross the blood-brain barrier. Some research also suggests the brain can use lactate as an alternative fuel, particularly during intense neural activity.So, while glucose is the go-to, the brain has backup fuel systems to ensure its continuous, high energy demand is met.