The brain is 2-3% of your body mass, but consumes _____ of your calories.

• A. 33-66%
• B. 5-10%
• C. 25-33%
• D. 50-75%

Answer: (C)

The brain uses a lot of energy relative to its small size because neurons are almost always active to maintain electrical signaling and drive brain functions. In adults, it accounts for about a quarter of daily energy expenditure—roughly 25-33% of total calories. So the best match is the 25-33% range. The other ranges are either too low (underestimating the brain’s continuous energy needs) or too high for typical daily intake.